diff --git a/Data/Sources/Data/PostRepository+Voting.swift b/Data/Sources/Data/PostRepository+Voting.swift
index e6dab419..c9c965dc 100644
--- a/Data/Sources/Data/PostRepository+Voting.swift
+++ b/Data/Sources/Data/PostRepository+Voting.swift
@@ -37,7 +37,23 @@ extension PostRepository {
         if containsLoginForm { throw HackersKitError.unauthenticated }
     }
 
-    // Unvote functionality removed
+    public func unvote(post: Post) async throws {
+        guard let voteLinks = post.voteLinks else { throw HackersKitError.unauthenticated }
+        guard let unvoteURL = voteLinks.unvote else {
+            throw HackersKitError.scraperError
+        }
+
+        let fullURLString = unvoteURL.absoluteString.hasPrefix("http")
+            ? unvoteURL.absoluteString
+            : urlBase + "/" + unvoteURL.absoluteString
+        guard let realURL = URL(string: fullURLString) else { throw HackersKitError.scraperError }
+
+        let response = try await networkManager.get(url: realURL)
+        let containsLoginForm =
+            response.contains("<form action=\"/login") ||
+            response.contains("You have to be logged in")
+        if containsLoginForm { throw HackersKitError.unauthenticated }
+    }
 
     public func upvote(comment: Domain.Comment, for _: Post) async throws {
         guard let voteLinks = comment.voteLinks else { throw HackersKitError.unauthenticated }
@@ -58,7 +74,23 @@ extension PostRepository {
         await MainActor.run { comment.upvoted = true }
     }
 
-    // Unvote functionality removed
+    public func unvote(comment: Domain.Comment, for _: Post) async throws {
+        guard let voteLinks = comment.voteLinks else { throw HackersKitError.unauthenticated }
+        guard let unvoteURL = voteLinks.unvote else {
+            throw HackersKitError.scraperError
+        }
+
+        let fullURLString = unvoteURL.absoluteString.hasPrefix("http")
+            ? unvoteURL.absoluteString
+            : urlBase + "/" + unvoteURL.absoluteString
+        guard let realURL = URL(string: fullURLString) else { throw HackersKitError.scraperError }
+
+        let response = try await networkManager.get(url: realURL)
+        let containsLoginForm = response.contains("<form action=\"/login")
+        if containsLoginForm { throw HackersKitError.unauthenticated }
+
+        await MainActor.run { comment.upvoted = false }
+    }
 
     // MARK: - Vote link extraction
 
diff --git a/DesignSystem/Sources/DesignSystem/Components/PostDisplayView.swift b/DesignSystem/Sources/DesignSystem/Components/PostDisplayView.swift
index 38aeebb1..7764ff10 100644
--- a/DesignSystem/Sources/DesignSystem/Components/PostDisplayView.swift
+++ b/DesignSystem/Sources/DesignSystem/Components/PostDisplayView.swift
@@ -16,6 +16,7 @@ public struct PostDisplayView: View {
     let showThumbnails: Bool
     let onThumbnailTap: (() -> Void)?
     let onUpvoteTap: (() async -> Bool)?
+    let onUnvoteTap: (() async -> Bool)?
     let onBookmarkTap: (() async -> Bool)?
     let onCommentsTap: (() -> Void)?
 
@@ -25,6 +26,7 @@ public struct PostDisplayView: View {
     @State private var displayedScore: Int
     @State private var displayedUpvoted: Bool
     @State private var displayedBookmarked: Bool
+    @State private var displayedVoteLinks: VoteLinks?
 
     public init(
         post: Post,
@@ -33,6 +35,7 @@ public struct PostDisplayView: View {
         showThumbnails: Bool = true,
         onThumbnailTap: (() -> Void)? = nil,
         onUpvoteTap: (() async -> Bool)? = nil,
+        onUnvoteTap: (() async -> Bool)? = nil,
         onBookmarkTap: (() async -> Bool)? = nil,
         onCommentsTap: (() -> Void)? = nil
     ) {
@@ -42,11 +45,13 @@ public struct PostDisplayView: View {
         self.showThumbnails = showThumbnails
         self.onThumbnailTap = onThumbnailTap
         self.onUpvoteTap = onUpvoteTap
+        self.onUnvoteTap = onUnvoteTap
         self.onBookmarkTap = onBookmarkTap
         self.onCommentsTap = onCommentsTap
         _displayedScore = State(initialValue: post.score)
         _displayedUpvoted = State(initialValue: post.upvoted)
         _displayedBookmarked = State(initialValue: post.isBookmarked)
+        _displayedVoteLinks = State(initialValue: post.voteLinks)
     }
 
     public var body: some View {
@@ -98,6 +103,7 @@ public struct PostDisplayView: View {
             displayedScore = post.score
             displayedUpvoted = post.upvoted
             displayedBookmarked = post.isBookmarked
+            displayedVoteLinks = post.voteLinks
         }
         .onChange(of: post.score) { newValue in
             displayedScore = newValue
@@ -108,6 +114,9 @@ public struct PostDisplayView: View {
         .onChange(of: post.isBookmarked) { newValue in
             displayedBookmarked = newValue
         }
+        .onChange(of: post.voteLinks) { newValue in
+            displayedVoteLinks = newValue
+        }
         .onChange(of: votingState?.score) { newValue in
             if let newValue {
                 displayedScore = newValue
@@ -124,8 +133,10 @@ public struct PostDisplayView: View {
         let score = displayedScore
         let isUpvoted = displayedUpvoted
         let isLoading = isSubmittingUpvote
-        let canVote = post.voteLinks?.upvote != nil
-        let canInteract = canVote && !isUpvoted && !isLoading
+        let currentVoteLinks = displayedVoteLinks ?? post.voteLinks
+        let canVote = currentVoteLinks?.upvote != nil
+        let canUnvote = currentVoteLinks?.unvote != nil
+        let canInteract = ((canVote && !isUpvoted) || (canUnvote && isUpvoted)) && !isLoading
         // Avoid keeping a disabled Button so the upvoted state retains the bright tint
         let (backgroundColor, textColor): (Color, Color) = {
             let style = AppColors.PillStyle.upvote(isActive: isUpvoted)
@@ -135,12 +146,19 @@ public struct PostDisplayView: View {
         }()
         let iconName = isUpvoted ? "arrow.up.circle.fill" : "arrow.up"
         let accessibilityLabel: String
+        let accessibilityHint: String
         if isLoading {
             accessibilityLabel = "Submitting vote"
+            accessibilityHint = ""
+        } else if isUpvoted && canUnvote {
+            accessibilityLabel = "\(score) points, upvoted"
+            accessibilityHint = "Double tap to unvote"
         } else if isUpvoted {
             accessibilityLabel = "\(score) points, upvoted"
+            accessibilityHint = ""
         } else {
             accessibilityLabel = "\(score) points"
+            accessibilityHint = "Double tap to upvote"
         }
 
         return pillView(
@@ -149,7 +167,7 @@ public struct PostDisplayView: View {
             textColor: textColor,
             backgroundColor: backgroundColor,
             accessibilityLabel: accessibilityLabel,
-            accessibilityHint: "Double tap to upvote",
+            accessibilityHint: accessibilityHint,
             isHighlighted: isUpvoted,
             isLoading: isLoading,
             isEnabled: canInteract,
@@ -171,6 +189,7 @@ public struct PostDisplayView: View {
             accessibilityLabel: "\(post.commentsCount) comments",
             isHighlighted: false,
             isLoading: false,
+            isEnabled: true,
             numericValue: post.commentsCount,
             action: onCommentsTap
         )
@@ -202,27 +221,81 @@ public struct PostDisplayView: View {
     }
 
     private func makeUpvoteAction() -> (() -> Void)? {
-        guard let onUpvoteTap else { return nil }
         return {
             guard !isSubmittingUpvote else { return }
-            isSubmittingUpvote = true
-            let previousScore = displayedScore
-            let previousUpvoted = displayedUpvoted
-            displayedUpvoted = true
-            displayedScore += 1
-            Task {
-                let success = await onUpvoteTap()
-                await MainActor.run {
-                    if !success {
-                        displayedScore = previousScore
-                        displayedUpvoted = previousUpvoted
+
+            let isCurrentlyUpvoted = displayedUpvoted
+            let currentVoteLinks = displayedVoteLinks ?? post.voteLinks
+            let canUnvote = currentVoteLinks?.unvote != nil
+
+            // If already upvoted and can unvote, perform unvote
+            if isCurrentlyUpvoted && canUnvote {
+                guard let onUnvoteTap else { return }
+                isSubmittingUpvote = true
+                let previousScore = displayedScore
+                let previousUpvoted = displayedUpvoted
+                let previousVoteLinks = currentVoteLinks
+                displayedUpvoted = false
+                displayedScore -= 1
+                displayedVoteLinks = VoteLinks(upvote: previousVoteLinks?.upvote, unvote: nil)
+                Task {
+                    let success = await onUnvoteTap()
+                    await MainActor.run {
+                        if !success {
+                            displayedScore = previousScore
+                            displayedUpvoted = previousUpvoted
+                            displayedVoteLinks = previousVoteLinks
+                        }
+                        isSubmittingUpvote = false
+                    }
+                }
+            } else {
+                // Perform upvote
+                guard let onUpvoteTap else { return }
+                isSubmittingUpvote = true
+                let previousScore = displayedScore
+                let previousUpvoted = displayedUpvoted
+                let previousVoteLinks = currentVoteLinks
+                displayedUpvoted = true
+                displayedScore += 1
+                displayedVoteLinks = derivedVoteLinks(afterUpvoteFrom: previousVoteLinks)
+                Task {
+                    let success = await onUpvoteTap()
+                    await MainActor.run {
+                        if !success {
+                            displayedScore = previousScore
+                            displayedUpvoted = previousUpvoted
+                            displayedVoteLinks = previousVoteLinks
+                        }
+                        isSubmittingUpvote = false
                     }
-                    isSubmittingUpvote = false
                 }
             }
         }
     }
 
+    private func derivedVoteLinks(afterUpvoteFrom voteLinks: VoteLinks?) -> VoteLinks? {
+        guard let voteLinks else { return nil }
+        if voteLinks.unvote != nil {
+            return voteLinks
+        }
+        guard let upvoteURL = voteLinks.upvote else {
+            return voteLinks
+        }
+        let absolute = upvoteURL.absoluteString
+        if absolute.contains("how=up"),
+           let unvoteURL = URL(string: absolute.replacingOccurrences(of: "how=up", with: "how=un"))
+        {
+            return VoteLinks(upvote: upvoteURL, unvote: unvoteURL)
+        }
+        if absolute.contains("how%3Dup"),
+           let unvoteURL = URL(string: absolute.replacingOccurrences(of: "how%3Dup", with: "how%3Dun"))
+        {
+            return VoteLinks(upvote: upvoteURL, unvote: unvoteURL)
+        }
+        return voteLinks
+    }
+
     private func makeBookmarkAction() -> (() -> Void)? {
         guard let onBookmarkTap else { return nil }
         return {
@@ -284,38 +357,68 @@ public struct PostDisplayView: View {
             Capsule()
                 .fill(backgroundColor)
         )
-        Button(action: action ?? {}) {
-            content
+        .overlay {
+            if isLoading {
+                Capsule()
+                    .fill(backgroundColor.opacity(0.6))
+            }
+        }
+        .overlay {
+            if isLoading {
+                ProgressView()
+                    .scaleEffect(0.6)
+                    .tint(textColor)
+            }
         }
-        .buttonStyle(.plain)
-        .accessibilityElement(children: .combine)
-        .accessibilityLabel(accessibilityLabel)
-        .accessibilityHint(accessibilityHint ?? "")
 
+        let shouldDisable = !isEnabled || isLoading
+        let shouldBeInteractive = isEnabled && !isLoading && action != nil
+
+        // If enabled but no action, render as static view to avoid disabled styling
+        if isEnabled && !isLoading && action == nil {
+            content
+                .accessibilityElement(children: .combine)
+                .accessibilityLabel(accessibilityLabel)
+                .accessibilityHint(accessibilityHint ?? "")
+        } else {
+            Button(action: action ?? {}) {
+                content
+            }
+            .buttonStyle(.plain)
+            .disabled(!shouldBeInteractive)
+            .allowsHitTesting(shouldBeInteractive)
+            .opacity(shouldDisable ? 0.6 : 1.0)
+            .accessibilityElement(children: .combine)
+            .accessibilityLabel(accessibilityLabel)
+            .accessibilityHint(accessibilityHint ?? "")
+        }
     }
 }
 
 public struct PostContextMenu: View {
     let post: Post
     let onVote: () -> Void
+    let onUnvote: () -> Void
     let onOpenLink: () -> Void
     let onShare: () -> Void
 
     public init(
         post: Post,
         onVote: @escaping () -> Void,
+        onUnvote: @escaping () -> Void = {},
         onOpenLink: @escaping () -> Void,
         onShare: @escaping () -> Void,
     ) {
         self.post = post
         self.onVote = onVote
+        self.onUnvote = onUnvote
         self.onOpenLink = onOpenLink
         self.onShare = onShare
     }
 
     public var body: some View {
         Group {
-            if post.voteLinks?.upvote != nil {
+            if post.voteLinks?.upvote != nil, !post.upvoted {
                 Button {
                     onVote()
                 } label: {
@@ -323,6 +426,14 @@ public struct PostContextMenu: View {
                 }
             }
 
+            if post.voteLinks?.unvote != nil, post.upvoted {
+                Button {
+                    onUnvote()
+                } label: {
+                    Label("Unvote", systemImage: "arrow.uturn.down")
+                }
+            }
+
             Divider()
 
             if !isHackerNewsItemURL(post.url) {
diff --git a/DesignSystem/Sources/DesignSystem/Components/VoteButton.swift b/DesignSystem/Sources/DesignSystem/Components/VoteButton.swift
index 91aed5a6..cf8d5377 100644
--- a/DesignSystem/Sources/DesignSystem/Components/VoteButton.swift
+++ b/DesignSystem/Sources/DesignSystem/Components/VoteButton.swift
@@ -44,11 +44,11 @@ public struct VoteButton: View {
                 }
             }
         }
-        .disabled(!votingState.canVote || votingState.isVoting)
+        .disabled((!votingState.canVote && !votingState.canUnvote) || votingState.isVoting)
         .scaleEffect(votingState.isVoting ? 0.95 : 1.0)
         .animation(.easeInOut(duration: 0.1), value: votingState.isVoting)
-        .accessibilityLabel(votingState.isUpvoted ? "Upvoted" : "Upvote")
-        .accessibilityHint(votingState.isUpvoted ? "Already upvoted" : (votingState.canVote ? "Double-tap to upvote" : "Voting unavailable"))
+        .accessibilityLabel(votingState.isUpvoted && votingState.canUnvote ? "Unvote" : (votingState.isUpvoted ? "Upvoted" : "Upvote"))
+        .accessibilityHint(votingState.isUpvoted && votingState.canUnvote ? "Double-tap to unvote" : (votingState.isUpvoted ? "Already upvoted" : (votingState.canVote ? "Double-tap to upvote" : "Voting unavailable")))
         .accessibilityValue({ () -> String in
             if let score = votingState.score { return "\(score) points" }
             return ""
diff --git a/DesignSystem/Sources/DesignSystem/Components/VotingContextMenuItems.swift b/DesignSystem/Sources/DesignSystem/Components/VotingContextMenuItems.swift
index 3dbf8ce2..435f0423 100644
--- a/DesignSystem/Sources/DesignSystem/Components/VotingContextMenuItems.swift
+++ b/DesignSystem/Sources/DesignSystem/Components/VotingContextMenuItems.swift
@@ -15,8 +15,9 @@ public enum VotingContextMenuItems {
     public static func postVotingMenuItems(
         for post: Post,
         onVote: @escaping @Sendable () -> Void,
+        onUnvote: @escaping @Sendable () -> Void = {},
     ) -> some View {
-        // Only show upvote if available and not already upvoted
+        // Show upvote if available and not already upvoted
         if post.voteLinks?.upvote != nil, !post.upvoted {
             Button {
                 onVote()
@@ -24,6 +25,14 @@ public enum VotingContextMenuItems {
                 Label("Upvote", systemImage: "arrow.up")
             }
         }
+        // Show unvote if available and already upvoted
+        if post.voteLinks?.unvote != nil, post.upvoted {
+            Button {
+                onUnvote()
+            } label: {
+                Label("Unvote", systemImage: "arrow.uturn.down")
+            }
+        }
     }
 
     // MARK: - Comment Voting Menu Items
@@ -32,8 +41,9 @@ public enum VotingContextMenuItems {
     public static func commentVotingMenuItems(
         for comment: Comment,
         onVote: @escaping @Sendable () -> Void,
+        onUnvote: @escaping @Sendable () -> Void = {},
     ) -> some View {
-        // Only show upvote if available and not already upvoted
+        // Show upvote if available and not already upvoted
         if comment.voteLinks?.upvote != nil, !comment.upvoted {
             Button {
                 onVote()
@@ -41,6 +51,14 @@ public enum VotingContextMenuItems {
                 Label("Upvote", systemImage: "arrow.up")
             }
         }
+        // Show unvote if available and already upvoted
+        if comment.voteLinks?.unvote != nil, comment.upvoted {
+            Button {
+                onUnvote()
+            } label: {
+                Label("Unvote", systemImage: "arrow.uturn.down")
+            }
+        }
     }
 
     // MARK: - Generic Votable Menu Items
@@ -49,8 +67,9 @@ public enum VotingContextMenuItems {
     public static func votingMenuItems(
         for item: some Votable,
         onVote: @escaping @Sendable () -> Void,
+        onUnvote: @escaping @Sendable () -> Void = {},
     ) -> some View {
-        // Only show upvote if available and not already upvoted
+        // Show upvote if available and not already upvoted
         if item.voteLinks?.upvote != nil, !item.upvoted {
             Button {
                 onVote()
@@ -58,6 +77,14 @@ public enum VotingContextMenuItems {
                 Label("Upvote", systemImage: "arrow.up")
             }
         }
+        // Show unvote if available and already upvoted
+        if item.voteLinks?.unvote != nil, item.upvoted {
+            Button {
+                onUnvote()
+            } label: {
+                Label("Unvote", systemImage: "arrow.uturn.down")
+            }
+        }
     }
 }
 
@@ -90,10 +117,11 @@ public extension View {
     func votingContextMenu(
         for item: some Votable,
         onVote: @escaping @Sendable () -> Void,
+        onUnvote: @escaping @Sendable () -> Void = {},
         additionalItems: @escaping () -> some View = { EmptyView() },
     ) -> some View {
         contextMenu {
-            VotingContextMenuItems.votingMenuItems(for: item, onVote: onVote)
+            VotingContextMenuItems.votingMenuItems(for: item, onVote: onVote, onUnvote: onUnvote)
             additionalItems()
         }
     }
diff --git a/Domain/Sources/Domain/Models.swift b/Domain/Sources/Domain/Models.swift
index ba211e7e..c4953e13 100644
--- a/Domain/Sources/Domain/Models.swift
+++ b/Domain/Sources/Domain/Models.swift
@@ -14,6 +14,7 @@ public struct VotingState: Sendable {
     public let isUpvoted: Bool
     public let score: Int?
     public let canVote: Bool
+    public let canUnvote: Bool
     public let isVoting: Bool
     public let error: Error?
 
@@ -21,12 +22,14 @@ public struct VotingState: Sendable {
         isUpvoted: Bool,
         score: Int? = nil,
         canVote: Bool,
+        canUnvote: Bool = false,
         isVoting: Bool = false,
         error: Error? = nil,
     ) {
         self.isUpvoted = isUpvoted
         self.score = score
         self.canVote = canVote
+        self.canUnvote = canUnvote
         self.isVoting = isVoting
         self.error = error
     }
diff --git a/Domain/Sources/Domain/VoteUseCase.swift b/Domain/Sources/Domain/VoteUseCase.swift
index 97e09d56..e082c3f3 100644
--- a/Domain/Sources/Domain/VoteUseCase.swift
+++ b/Domain/Sources/Domain/VoteUseCase.swift
@@ -10,4 +10,6 @@ import Foundation
 public protocol VoteUseCase: Sendable {
     func upvote(post: Post) async throws
     func upvote(comment: Comment, for post: Post) async throws
+    func unvote(post: Post) async throws
+    func unvote(comment: Comment, for post: Post) async throws
 }
diff --git a/Domain/Sources/Domain/VotingStateProvider.swift b/Domain/Sources/Domain/VotingStateProvider.swift
index 80b55691..f721d4a5 100644
--- a/Domain/Sources/Domain/VotingStateProvider.swift
+++ b/Domain/Sources/Domain/VotingStateProvider.swift
@@ -12,6 +12,7 @@ import Foundation
 public protocol VotingStateProvider: Sendable {
     func votingState(for item: any Votable) -> VotingState
     func upvote(item: any Votable) async throws
+    func unvote(item: any Votable) async throws
 }
 
 // MARK: - Default Implementation
@@ -29,6 +30,7 @@ public final class DefaultVotingStateProvider: VotingStateProvider, Sendable {
             isUpvoted: item.upvoted,
             score: score,
             canVote: item.voteLinks?.upvote != nil,
+            canUnvote: item.voteLinks?.unvote != nil,
             isVoting: false,
         )
     }
@@ -44,16 +46,33 @@ public final class DefaultVotingStateProvider: VotingStateProvider, Sendable {
             throw HackersKitError.requestFailure
         }
     }
+
+    public func unvote(item: any Votable) async throws {
+        switch item {
+        case let post as Post:
+            try await voteUseCase.unvote(post: post)
+        case let comment as Comment:
+            // For comments, we need the parent post - this will be handled by the calling code
+            throw HackersKitError.requestFailure
+        default:
+            throw HackersKitError.requestFailure
+        }
+    }
 }
 
 // MARK: - Comment-Specific Voting State Provider
 
 public protocol CommentVotingStateProvider: Sendable {
     func upvoteComment(_ comment: Comment, for post: Post) async throws
+    func unvoteComment(_ comment: Comment, for post: Post) async throws
 }
 
 extension DefaultVotingStateProvider: CommentVotingStateProvider {
     public func upvoteComment(_ comment: Comment, for post: Post) async throws {
         try await voteUseCase.upvote(comment: comment, for: post)
     }
+
+    public func unvoteComment(_ comment: Comment, for post: Post) async throws {
+        try await voteUseCase.unvote(comment: comment, for: post)
+    }
 }
diff --git a/Features/Comments/Sources/Comments/CommentsComponents.swift b/Features/Comments/Sources/Comments/CommentsComponents.swift
index eaaf2490..c874de87 100644
--- a/Features/Comments/Sources/Comments/CommentsComponents.swift
+++ b/Features/Comments/Sources/Comments/CommentsComponents.swift
@@ -38,14 +38,11 @@ struct CommentsContentView: View {
                     PostHeader(
                         post: post,
                         votingViewModel: votingViewModel,
+                        isLoadingComments: viewModel.isLoading,
                         showThumbnails: viewModel.showThumbnails,
                         onLinkTap: { handleLinkTap() },
-                        onUpvoteApplied: {
-                            if var currentPost = viewModel.post, !currentPost.upvoted {
-                                currentPost.upvoted = true
-                                currentPost.score += 1
-                                viewModel.post = currentPost
-                            }
+                        onPostUpdated: { updatedPost in
+                            viewModel.post = updatedPost
                         },
                         onBookmarkToggle: { await viewModel.toggleBookmark() }
                     )
@@ -57,28 +54,43 @@ struct CommentsContentView: View {
                         )
                     })
                     .listRowSeparator(.hidden)
-                    .if(post.voteLinks?.upvote != nil && !post.upvoted) { view in
+                    .if((post.voteLinks?.upvote != nil && !post.upvoted) || (post.voteLinks?.unvote != nil && post.upvoted)) { view in
                         view.swipeActions(edge: .leading, allowsFullSwipe: true) {
-                            Button {
-                                Task {
-                                    var mutablePost = post
-                                    await votingViewModel.upvote(post: &mutablePost)
-                                    await MainActor.run {
-                                        if mutablePost.upvoted,
-                                           var currentPost = viewModel.post,
-                                           !currentPost.upvoted
-                                        {
-                                            currentPost.upvoted = true
-                                            currentPost.score += 1
-                                            viewModel.post = currentPost
+                            if post.upvoted && post.voteLinks?.unvote != nil {
+                                Button {
+                                    guard !viewModel.isLoading else { return }
+                                    Task {
+                                        var mutablePost = post
+                                        await votingViewModel.unvote(post: &mutablePost)
+                                        await MainActor.run {
+                                            viewModel.post = mutablePost
                                         }
                                     }
+                                } label: {
+                                    Image(systemName: "arrow.uturn.down")
                                 }
-                            } label: {
-                                Image(systemName: "arrow.up")
+                                .tint(.orange)
+                                .accessibilityLabel("Unvote")
+                                .disabled(viewModel.isLoading)
+                            } else {
+                                Button {
+                                    guard !viewModel.isLoading else { return }
+                                    Task {
+                                        var mutablePost = post
+                                        await votingViewModel.upvote(post: &mutablePost)
+                                        await MainActor.run {
+                                            if mutablePost.upvoted {
+                                                viewModel.post = mutablePost
+                                            }
+                                        }
+                                    }
+                                } label: {
+                                    Image(systemName: "arrow.up")
+                                }
+                                .tint(AppColors.upvotedColor)
+                                .accessibilityLabel("Upvote")
+                                .disabled(viewModel.isLoading)
                             }
-                            .tint(AppColors.upvotedColor)
-                            .accessibilityLabel("Upvote")
                         }
                     }
 
@@ -163,18 +175,30 @@ struct CommentsForEach: View {
                     value: [comment.id: geometry.frame(in: .global)],
                 )
             })
-            .listRowSeparator(.visible)
-            .if(comment.voteLinks?.upvote != nil && !comment.upvoted) { view in
+            .listRowSeparator(.hidden)
+            .if((comment.voteLinks?.upvote != nil && !comment.upvoted) || (comment.voteLinks?.unvote != nil && comment.upvoted)) { view in
                 view.swipeActions(edge: .leading, allowsFullSwipe: true) {
-                    Button {
-                        Task {
-                            await votingViewModel.upvote(comment: comment, in: post)
+                    if comment.upvoted && comment.voteLinks?.unvote != nil {
+                        Button {
+                            Task {
+                                await votingViewModel.unvote(comment: comment, in: post)
+                            }
+                        } label: {
+                            Image(systemName: "arrow.uturn.down")
                         }
-                    } label: {
-                        Image(systemName: "arrow.up")
+                        .tint(.orange)
+                        .accessibilityLabel("Unvote")
+                    } else {
+                        Button {
+                            Task {
+                                await votingViewModel.upvote(comment: comment, in: post)
+                            }
+                        } label: {
+                            Image(systemName: "arrow.up")
+                        }
+                        .tint(AppColors.upvotedColor)
+                        .accessibilityLabel("Upvote")
                     }
-                    .tint(AppColors.upvotedColor)
-                    .accessibilityLabel("Upvote")
                 }
             }
             .swipeActions(edge: .trailing) {
@@ -194,9 +218,10 @@ struct CommentsForEach: View {
 struct PostHeader: View {
     let post: Post
     let votingViewModel: VotingViewModel
+    let isLoadingComments: Bool
     let showThumbnails: Bool
     let onLinkTap: () -> Void
-    let onUpvoteApplied: @Sendable () -> Void
+    let onPostUpdated: @Sendable (Post) -> Void
     let onBookmarkToggle: @Sendable () async -> Bool
 
     var body: some View {
@@ -207,6 +232,7 @@ struct PostHeader: View {
             showThumbnails: showThumbnails,
             onThumbnailTap: { onLinkTap() },
             onUpvoteTap: { await handleUpvote() },
+            onUnvoteTap: { await handleUnvote() },
             onBookmarkTap: { await onBookmarkToggle() }
         )
         .contentShape(Rectangle())
@@ -215,6 +241,7 @@ struct PostHeader: View {
             VotingContextMenuItems.postVotingMenuItems(
                 for: post,
                 onVote: { Task { await handleUpvote() } },
+                onUnvote: { Task { await handleUnvote() } }
             )
 
             Divider()
@@ -230,6 +257,7 @@ struct PostHeader: View {
     }
 
     private func handleUpvote() async -> Bool {
+        guard !isLoadingComments else { return false }
         guard votingViewModel.canVote(item: post), !post.upvoted else { return false }
 
         var mutablePost = post
@@ -238,12 +266,29 @@ struct PostHeader: View {
 
         if wasUpvoted {
             await MainActor.run {
-                onUpvoteApplied()
+                onPostUpdated(mutablePost)
             }
         }
 
         return wasUpvoted
     }
+
+    private func handleUnvote() async -> Bool {
+        guard !isLoadingComments else { return true }
+        guard votingViewModel.canUnvote(item: post), post.upvoted else { return true }
+
+        var mutablePost = post
+        await votingViewModel.unvote(post: &mutablePost)
+        let wasUnvoted = !mutablePost.upvoted
+
+        if wasUnvoted {
+            await MainActor.run {
+                onPostUpdated(mutablePost)
+            }
+        }
+
+        return wasUnvoted
+    }
 }
 
 struct CommentRow: View {
@@ -289,6 +334,7 @@ struct CommentRow: View {
                             isUpvoted: comment.upvoted,
                             score: nil,
                             canVote: comment.voteLinks?.upvote != nil,
+                            canUnvote: comment.voteLinks?.unvote != nil,
                             isVoting: votingViewModel.isVoting,
                             error: votingViewModel.lastError,
                         ),
@@ -319,6 +365,9 @@ struct CommentRow: View {
                 onVote: {
                     Task { await votingViewModel.upvote(comment: comment, in: post) }
                 },
+                onUnvote: {
+                    Task { await votingViewModel.unvote(comment: comment, in: post) }
+                }
             )
             Button { UIPasteboard.general.string = comment.text.strippingHTML() } label: {
                 Label("Copy", systemImage: "doc.on.doc")
diff --git a/Features/Comments/Sources/Comments/CommentsView.swift b/Features/Comments/Sources/Comments/CommentsView.swift
index 24714686..e98d7142 100644
--- a/Features/Comments/Sources/Comments/CommentsView.swift
+++ b/Features/Comments/Sources/Comments/CommentsView.swift
@@ -114,6 +114,12 @@ public struct CommentsView<NavigationStore: NavigationStoreProtocol>: View {
         }
         .task {
             votingViewModel.navigationStore = navigationStore
+            // Set up callback to update navigation store when post changes
+            viewModel.onPostUpdated = { [weak navigationStore] updatedPost in
+                if let updatedPost {
+                    navigationStore?.selectedPost = updatedPost
+                }
+            }
             await viewModel.loadComments()
             if let targetID = pendingCommentID {
                 _ = await viewModel.revealComment(withId: targetID)
diff --git a/Features/Comments/Sources/Comments/CommentsViewModel.swift b/Features/Comments/Sources/Comments/CommentsViewModel.swift
index 2d95a66a..cacc87c3 100644
--- a/Features/Comments/Sources/Comments/CommentsViewModel.swift
+++ b/Features/Comments/Sources/Comments/CommentsViewModel.swift
@@ -14,12 +14,18 @@ import SwiftUI
 @Observable
 public final class CommentsViewModel: @unchecked Sendable {
     public let postID: Int
-    public var post: Post?
+    public var post: Post? {
+        didSet {
+            onPostUpdated?(post)
+        }
+    }
     public var visibleComments: [Comment] = []
     public var showThumbnails: Bool
 
     // Callback for when comments are loaded (used for HTML parsing in the view layer)
     public var onCommentsLoaded: (([Comment]) -> Void)?
+    // Callback for when post is updated
+    public var onPostUpdated: ((Post?) -> Void)?
 
     private let postUseCase: any PostUseCase
     private let commentUseCase: any CommentUseCase
diff --git a/Features/Comments/Tests/CommentsTests/CommentsViewModelTests.swift b/Features/Comments/Tests/CommentsTests/CommentsViewModelTests.swift
index 746d2e97..48a60ae6 100644
--- a/Features/Comments/Tests/CommentsTests/CommentsViewModelTests.swift
+++ b/Features/Comments/Tests/CommentsTests/CommentsViewModelTests.swift
@@ -631,6 +631,18 @@ final class MockVoteUseCase: VoteUseCase, @unchecked Sendable {
             throw MockError.testError
         }
     }
+
+    func unvote(post _: Post) async throws {
+        if shouldThrowError {
+            throw MockError.testError
+        }
+    }
+
+    func unvote(comment _: Domain.Comment, for _: Post) async throws {
+        if shouldThrowError {
+            throw MockError.testError
+        }
+    }
 }
 
 final class StubSettingsUseCase: SettingsUseCase, @unchecked Sendable {
diff --git a/Features/Feed/Sources/Feed/FeedView.swift b/Features/Feed/Sources/Feed/FeedView.swift
index f371e2a4..8d5aa3cf 100644
--- a/Features/Feed/Sources/Feed/FeedView.swift
+++ b/Features/Feed/Sources/Feed/FeedView.swift
@@ -101,6 +101,13 @@ public struct FeedView<NavigationStore: NavigationStoreProtocol>: View {
             votingViewModel.navigationStore = navigationStore
             await viewModel.loadFeed()
         }
+        .onChange(of: navigationStore.selectedPost) { oldPost, newPost in
+            // When selectedPost changes in navigation store (e.g., from comments view),
+            // update it in the feed
+            if let updatedPost = newPost {
+                viewModel.replacePost(updatedPost)
+            }
+        }
         .alert(
             "Vote Error",
             isPresented: Binding(
@@ -187,8 +194,8 @@ public struct FeedView<NavigationStore: NavigationStoreProtocol>: View {
             showThumbnails: viewModel.showThumbnails,
             onLinkTap: { handleLinkTap(post: post) },
             onCommentsTap: isSidebar ? nil : { navigationStore.showPost(post) },
-            onUpvoteApplied: { postId in
-                viewModel.applyLocalUpvote(to: postId)
+            onPostUpdated: { updatedPost in
+                viewModel.replacePost(updatedPost)
             },
             onBookmarkToggle: {
                 await viewModel.toggleBookmark(for: post)
@@ -205,7 +212,7 @@ public struct FeedView<NavigationStore: NavigationStoreProtocol>: View {
                 }
             }
         }
-        .if(post.voteLinks?.upvote != nil && !post.upvoted) { view in
+        .if((post.voteLinks?.upvote != nil && !post.upvoted) || (post.voteLinks?.unvote != nil && post.upvoted)) { view in
             view.swipeActions(edge: .leading, allowsFullSwipe: true) {
                 voteSwipeAction(for: post)
             }
@@ -217,21 +224,44 @@ public struct FeedView<NavigationStore: NavigationStoreProtocol>: View {
 
     @ViewBuilder
     private func voteSwipeAction(for post: Domain.Post) -> some View {
-        Button {
-            Task {
-                var mutablePost = post
-                await votingViewModel.upvote(post: &mutablePost)
-                await MainActor.run {
-                    if mutablePost.upvoted {
-                        viewModel.applyLocalUpvote(to: post.id)
+        if post.upvoted && post.voteLinks?.unvote != nil {
+            // Unvote action
+            Button {
+                Task {
+                    var mutablePost = post
+                    await votingViewModel.unvote(post: &mutablePost)
+                    await MainActor.run {
+                        if !mutablePost.upvoted {
+                            if let existingLinks = mutablePost.voteLinks {
+                                mutablePost.voteLinks = VoteLinks(upvote: existingLinks.upvote, unvote: nil)
+                            }
+                            viewModel.replacePost(mutablePost)
+                        }
                     }
                 }
+            } label: {
+                Image(systemName: "arrow.uturn.down")
             }
-        } label: {
-            Image(systemName: "arrow.up")
+            .tint(.orange)
+            .accessibilityLabel("Unvote")
+        } else {
+            // Upvote action
+            Button {
+                Task {
+                    var mutablePost = post
+                    await votingViewModel.upvote(post: &mutablePost)
+                    await MainActor.run {
+                        if mutablePost.upvoted {
+                            viewModel.replacePost(mutablePost)
+                        }
+                    }
+                }
+            } label: {
+                Image(systemName: "arrow.up")
+            }
+            .tint(AppColors.upvotedColor)
+            .accessibilityLabel("Upvote")
         }
-        .tint(AppColors.upvotedColor)
-        .accessibilityLabel("Upvote")
     }
 
     @ViewBuilder
@@ -244,11 +274,25 @@ public struct FeedView<NavigationStore: NavigationStoreProtocol>: View {
                     await votingViewModel.upvote(post: &mutablePost)
                     await MainActor.run {
                         if mutablePost.upvoted {
-                            viewModel.applyLocalUpvote(to: post.id)
+                            viewModel.replacePost(mutablePost)
                         }
                     }
                 }
             },
+            onUnvote: {
+                Task {
+                    var mutablePost = post
+                    await votingViewModel.unvote(post: &mutablePost)
+                    await MainActor.run {
+                        if !mutablePost.upvoted {
+                            if let existingLinks = mutablePost.voteLinks {
+                                mutablePost.voteLinks = VoteLinks(upvote: existingLinks.upvote, unvote: nil)
+                            }
+                            viewModel.replacePost(mutablePost)
+                        }
+                    }
+                }
+            }
         )
 
         Divider()
@@ -348,7 +392,7 @@ struct PostRowView: View {
     let onLinkTap: (() -> Void)?
     let onCommentsTap: (() -> Void)?
     let showThumbnails: Bool
-    let onUpvoteApplied: ((Int) -> Void)?
+    let onPostUpdated: ((Domain.Post) -> Void)?
     let onBookmarkToggle: (() async -> Bool)?
 
     init(post: Domain.Post,
@@ -356,7 +400,7 @@ struct PostRowView: View {
          showThumbnails: Bool = true,
          onLinkTap: (() -> Void)? = nil,
          onCommentsTap: (() -> Void)? = nil,
-         onUpvoteApplied: ((Int) -> Void)? = nil,
+         onPostUpdated: ((Domain.Post) -> Void)? = nil,
          onBookmarkToggle: (() async -> Bool)? = nil)
     {
         self.post = post
@@ -364,7 +408,7 @@ struct PostRowView: View {
         self.onLinkTap = onLinkTap
         self.onCommentsTap = onCommentsTap
         self.showThumbnails = showThumbnails
-        self.onUpvoteApplied = onUpvoteApplied
+        self.onPostUpdated = onPostUpdated
         self.onBookmarkToggle = onBookmarkToggle
     }
 
@@ -376,6 +420,7 @@ struct PostRowView: View {
             showThumbnails: showThumbnails,
             onThumbnailTap: onLinkTap,
             onUpvoteTap: { await handleUpvoteTap() },
+            onUnvoteTap: { await handleUnvoteTap() },
             onBookmarkTap: {
                 guard let onBookmarkToggle else { return post.isBookmarked }
                 return await onBookmarkToggle()
@@ -404,10 +449,29 @@ struct PostRowView: View {
 
         if wasUpvoted {
             await MainActor.run {
-                onUpvoteApplied?(mutablePost.id)
+                onPostUpdated?(mutablePost)
             }
         }
 
         return wasUpvoted
     }
+
+    private func handleUnvoteTap() async -> Bool {
+        guard votingViewModel.canUnvote(item: post), post.upvoted else { return true }
+
+        var mutablePost = post
+        await votingViewModel.unvote(post: &mutablePost)
+        let wasUnvoted = !mutablePost.upvoted
+
+        if wasUnvoted {
+            if let existingLinks = mutablePost.voteLinks {
+                mutablePost.voteLinks = VoteLinks(upvote: existingLinks.upvote, unvote: nil)
+            }
+            await MainActor.run {
+                onPostUpdated?(mutablePost)
+            }
+        }
+
+        return wasUnvoted
+    }
 }
diff --git a/Features/Feed/Sources/Feed/FeedViewModel.swift b/Features/Feed/Sources/Feed/FeedViewModel.swift
index 628a4a4d..60268121 100644
--- a/Features/Feed/Sources/Feed/FeedViewModel.swift
+++ b/Features/Feed/Sources/Feed/FeedViewModel.swift
@@ -241,14 +241,9 @@ public final class FeedViewModel: @unchecked Sendable {
         if let index = feedLoader.data.firstIndex(where: { $0.id == updatedPost.id }) {
             feedLoader.data[index] = updatedPost
         }
-    }
-
-    @MainActor
-    public func applyLocalUpvote(to postId: Int) {
-        guard let index = feedLoader.data.firstIndex(where: { $0.id == postId }) else { return }
-        guard feedLoader.data[index].upvoted == false else { return }
-        feedLoader.data[index].upvoted = true
-        feedLoader.data[index].score += 1
+        if let searchIndex = searchResults.firstIndex(where: { $0.id == updatedPost.id }) {
+            searchResults[searchIndex] = updatedPost
+        }
     }
 
     @MainActor
diff --git a/Features/Feed/Tests/FeedTests/FeedViewModelTests.swift b/Features/Feed/Tests/FeedTests/FeedViewModelTests.swift
index 69531959..de042449 100644
--- a/Features/Feed/Tests/FeedTests/FeedViewModelTests.swift
+++ b/Features/Feed/Tests/FeedTests/FeedViewModelTests.swift
@@ -359,6 +359,14 @@ private final class StubVoteUseCase: VoteUseCase, @unchecked Sendable {
     func upvote(comment _: Domain.Comment, for _: Post) async throws {
         if shouldThrow { throw StubError.network }
     }
+
+    func unvote(post _: Post) async throws {
+        if shouldThrow { throw StubError.network }
+    }
+
+    func unvote(comment _: Domain.Comment, for _: Post) async throws {
+        if shouldThrow { throw StubError.network }
+    }
 }
 
 private final class StubBookmarksUseCase: BookmarksUseCase, @unchecked Sendable {
diff --git a/Features/Feed/Tests/FeedTests/FeedViewTests.swift b/Features/Feed/Tests/FeedTests/FeedViewTests.swift
index 8496a0aa..e7d3c326 100644
--- a/Features/Feed/Tests/FeedTests/FeedViewTests.swift
+++ b/Features/Feed/Tests/FeedTests/FeedViewTests.swift
@@ -113,7 +113,9 @@ struct FeedViewTests {
             // Not used in feed
         }
 
-        // Unvote removed
+        func unvote(post _: Post) async throws {}
+
+        func unvote(comment _: Domain.Comment, for _: Post) async throws {}
     }
 
     final class MockBookmarksUseCase: BookmarksUseCase, @unchecked Sendable {
diff --git a/Shared/Sources/Shared/ViewModels/VotingViewModel.swift b/Shared/Sources/Shared/ViewModels/VotingViewModel.swift
index f7d5d92a..6c430d0f 100644
--- a/Shared/Sources/Shared/ViewModels/VotingViewModel.swift
+++ b/Shared/Sources/Shared/ViewModels/VotingViewModel.swift
@@ -42,6 +42,7 @@ public final class VotingViewModel {
         guard !post.upvoted else { return }
 
         let originalScore = post.score
+        let originalVoteLinks = post.voteLinks
 
         // Create a copy of the post with the original state for the voting provider
         var postForVoting = post
@@ -51,6 +52,7 @@ public final class VotingViewModel {
         // Optimistic UI update
         post.upvoted = true
         post.score += 1
+        post.voteLinks = ensureUnvoteLinkIfPossible(from: originalVoteLinks)
 
         isVoting = true
         lastError = nil
@@ -62,6 +64,7 @@ public final class VotingViewModel {
             // Revert optimistic changes on error
             post.upvoted = false
             post.score = originalScore
+            post.voteLinks = originalVoteLinks
 
             await handleUnauthenticatedIfNeeded(error)
         }
@@ -69,7 +72,41 @@ public final class VotingViewModel {
         isVoting = false
     }
 
-    // Unvote removed
+    public func unvote(post: inout Post) async {
+        guard post.upvoted else { return }
+
+        let originalScore = post.score
+
+        // Create a copy of the post with the original state for the voting provider
+        var postForVoting = post
+        postForVoting.upvoted = true
+        postForVoting.score = originalScore
+
+        // Optimistic UI update
+        post.upvoted = false
+        post.score -= 1
+
+        // Clear unvote link after successful unvote
+        if let existingLinks = post.voteLinks {
+            post.voteLinks = VoteLinks(upvote: existingLinks.upvote, unvote: nil)
+        }
+
+        isVoting = true
+        lastError = nil
+
+        do {
+            try await votingStateProvider.unvote(item: postForVoting)
+
+        } catch {
+            // Revert optimistic changes on error
+            post.upvoted = true
+            post.score = originalScore
+
+            await handleUnauthenticatedIfNeeded(error)
+        }
+
+        isVoting = false
+    }
 
     // MARK: - Comment Voting
 
@@ -80,9 +117,11 @@ public final class VotingViewModel {
         // Create a copy of the comment with the original state for the voting provider
         var commentForVoting = comment
         commentForVoting.upvoted = false
+        let originalVoteLinks = comment.voteLinks
 
         // Optimistic UI update
         comment.upvoted = true
+        comment.voteLinks = ensureUnvoteLinkIfPossible(from: originalVoteLinks)
 
         isVoting = true
         lastError = nil
@@ -92,6 +131,7 @@ public final class VotingViewModel {
         } catch {
             // Revert optimistic changes on error
             comment.upvoted = false
+            comment.voteLinks = originalVoteLinks
 
             // Check if error is unauthenticated and show login
             await handleUnauthenticatedIfNeeded(error)
@@ -100,7 +140,31 @@ public final class VotingViewModel {
         isVoting = false
     }
 
-    // Comment unvote removed
+    public func unvote(comment: Comment, in post: Post) async {
+        guard comment.upvoted else { return }
+
+        // Create a copy of the comment with the original state for the voting provider
+        var commentForVoting = comment
+        commentForVoting.upvoted = true
+
+        // Optimistic UI update
+        comment.upvoted = false
+
+        isVoting = true
+        lastError = nil
+
+        do {
+            try await commentVotingStateProvider.unvoteComment(commentForVoting, for: post)
+        } catch {
+            // Revert optimistic changes on error
+            comment.upvoted = true
+
+            // Check if error is unauthenticated and show login
+            await handleUnauthenticatedIfNeeded(error)
+        }
+
+        isVoting = false
+    }
 
     // MARK: - State Helpers
 
@@ -110,6 +174,7 @@ public final class VotingViewModel {
             isUpvoted: baseState.isUpvoted,
             score: baseState.score,
             canVote: baseState.canVote,
+            canUnvote: baseState.canUnvote,
             isVoting: isVoting,
             error: lastError
         )
@@ -119,6 +184,10 @@ public final class VotingViewModel {
         item.voteLinks?.upvote != nil
     }
 
+    public func canUnvote(item: any Votable) -> Bool {
+        item.voteLinks?.unvote != nil
+    }
+
     public func clearError() {
         lastError = nil
     }
@@ -141,4 +210,33 @@ public final class VotingViewModel {
         // Prompt login
         navigationStore?.showLogin()
     }
+
+    private func ensureUnvoteLinkIfPossible(from voteLinks: VoteLinks?) -> VoteLinks? {
+        guard let voteLinks else { return nil }
+        if voteLinks.unvote != nil {
+            return voteLinks
+        }
+        guard let upvoteURL = voteLinks.upvote else {
+            return voteLinks
+        }
+
+        guard let derivedUnvoteURL = deriveUnvoteURL(from: upvoteURL) else {
+            return voteLinks
+        }
+        return VoteLinks(upvote: voteLinks.upvote, unvote: derivedUnvoteURL)
+    }
+
+    private func deriveUnvoteURL(from upvoteURL: URL) -> URL? {
+        let absoluteString = upvoteURL.absoluteString
+
+        if absoluteString.contains("how=up") {
+            return URL(string: absoluteString.replacingOccurrences(of: "how=up", with: "how=un"))
+        }
+
+        if absoluteString.contains("how%3Dup") {
+            return URL(string: absoluteString.replacingOccurrences(of: "how%3Dup", with: "how%3Dun"))
+        }
+
+        return nil
+    }
 }
diff --git a/Shared/Tests/SharedTests/DependencyContainerTests.swift b/Shared/Tests/SharedTests/DependencyContainerTests.swift
index 9d51b3ba..a3641eae 100644
--- a/Shared/Tests/SharedTests/DependencyContainerTests.swift
+++ b/Shared/Tests/SharedTests/DependencyContainerTests.swift
@@ -121,6 +121,8 @@ private final class StubPostRepository: PostUseCase, VoteUseCase, CommentUseCase
     func getComments(for _: Post) async throws -> [Domain.Comment] { [] }
     func upvote(post _: Post) async throws {}
     func upvote(comment _: Domain.Comment, for _: Post) async throws {}
+    func unvote(post _: Post) async throws {}
+    func unvote(comment _: Domain.Comment, for _: Post) async throws {}
 }
 
 private final class StubSettingsUseCase: SettingsUseCase, @unchecked Sendable {
@@ -145,6 +147,10 @@ private final class StubVotingStateProvider:
     func upvoteComment(_ comment: Domain.Comment, for _: Post) async throws {
         comment.upvoted = true
     }
+    func unvote(item _: any Votable) async throws {}
+    func unvoteComment(_ comment: Domain.Comment, for _: Post) async throws {
+        comment.upvoted = false
+    }
 }
 
 private final class StubAuthenticationUseCase: AuthenticationUseCase, @unchecked Sendable {
diff --git a/Shared/Tests/SharedTests/VotingViewModelTests.swift b/Shared/Tests/SharedTests/VotingViewModelTests.swift
index ca8be012..d9084be8 100644
--- a/Shared/Tests/SharedTests/VotingViewModelTests.swift
+++ b/Shared/Tests/SharedTests/VotingViewModelTests.swift
@@ -42,6 +42,8 @@ struct VotingViewModelTests {
             upvoteCalled = true
             if let errorToThrow { throw errorToThrow }
         }
+
+        func unvote(item _: any Votable) async throws {}
     }
 
     final class MockCommentVotingStateProvider: CommentVotingStateProvider, @unchecked Sendable {
@@ -54,6 +56,8 @@ struct VotingViewModelTests {
                 throw HackersKitError.requestFailure
             }
         }
+
+        func unvoteComment(_: Domain.Comment, for _: Post) async throws {}
     }
 
     final class MockAuthenticationUseCase: AuthenticationUseCase, @unchecked Sendable {
@@ -131,6 +135,42 @@ struct VotingViewModelTests {
         #expect(post.upvoted == false && post.score == 10, "Optimistic state should be reverted")
     }
 
+    @Test("Post upvote synthesizes unvote URL when missing")
+    @MainActor
+    func postUpvoteSynthesizesUnvoteURL() async throws {
+        mockVotingStateProvider.upvoteCalled = false
+
+        var post = Post(
+            id: 42,
+            url: URL(string: "https://example.com")!,
+            title: "Synth Test",
+            age: "1h",
+            commentsCount: 2,
+            by: "tester",
+            score: 5,
+            postType: .news,
+            upvoted: false,
+            voteLinks: VoteLinks(
+                upvote: URL(string: "https://news.ycombinator.com/vote?id=42&how=up&auth=abc123&goto=news")!,
+                unvote: nil
+            )
+        )
+
+        await votingViewModel.upvote(post: &post)
+
+        #expect(mockVotingStateProvider.upvoteCalled, "Upvote should be attempted")
+
+        guard let unvoteURL = post.voteLinks?.unvote else {
+            Issue.record("Expected synthesized unvote URL")
+            return
+        }
+
+        let absolute = unvoteURL.absoluteString
+        #expect(absolute.contains("how=un"), "Unvote URL should set how=un")
+        #expect(absolute.contains("auth=abc123"), "Unvote URL should preserve auth token")
+        #expect(absolute.contains("goto=news"), "Unvote URL should preserve goto parameter")
+    }
+
     // MARK: - Comment Voting Tests
 
     @Test("Comment voting with MainActor")
@@ -168,6 +208,50 @@ struct VotingViewModelTests {
         #expect(comment.upvoted == true, "Comment should be marked as upvoted after upvote")
     }
 
+    @Test("Comment upvote synthesizes unvote URL when missing")
+    @MainActor
+    func commentUpvoteSynthesizesUnvoteURL() async throws {
+        mockCommentVotingStateProvider.shouldThrow = false
+        mockCommentVotingStateProvider.upvoteCommentCalled = false
+
+        let voteLinks = VoteLinks(
+            upvote: URL(string: "vote?id=123&how=up&auth=xyz&goto=item%3Fid%3D456")!,
+            unvote: nil
+        )
+        let comment = Domain.Comment(
+            id: 123,
+            age: "1h",
+            text: "Test comment",
+            by: "user",
+            level: 0,
+            upvoted: false,
+            voteLinks: voteLinks
+        )
+
+        let post = Post(
+            id: 456,
+            url: URL(string: "https://example.com")!,
+            title: "Test Post",
+            age: "2h",
+            commentsCount: 1,
+            by: "author",
+            score: 10,
+            postType: .news,
+            upvoted: false
+        )
+
+        await votingViewModel.upvote(comment: comment, in: post)
+
+        #expect(mockCommentVotingStateProvider.upvoteCommentCalled, "Upvote should be attempted")
+        guard let commentUnvote = comment.voteLinks?.unvote else {
+            Issue.record("Expected synthesized unvote URL for comment")
+            return
+        }
+        let absolute = commentUnvote.absoluteString
+        #expect(absolute.contains("how=un"), "Unvote URL should use how=un")
+        #expect(absolute.contains("auth=xyz"), "Auth token should be preserved")
+    }
+
     @Test("Comment voting error handling")
     @MainActor
     func commentVotingErrorHandling() async throws {