diff --git a/FirebaseAI/Sources/Types/Internal/InternalPart.swift b/FirebaseAI/Sources/Types/Internal/InternalPart.swift
index d543fb80f38..5a655062729 100644
--- a/FirebaseAI/Sources/Types/Internal/InternalPart.swift
+++ b/FirebaseAI/Sources/Types/Internal/InternalPart.swift
@@ -45,10 +45,12 @@ struct FileData: Codable, Equatable, Sendable {
 struct FunctionCall: Equatable, Sendable {
   let name: String
   let args: JSONObject
+  let id: String?
 
-  init(name: String, args: JSONObject) {
+  init(name: String, args: JSONObject, id: String?) {
     self.name = name
     self.args = args
+    self.id = id
   }
 }
 
@@ -56,10 +58,12 @@ struct FunctionCall: Equatable, Sendable {
 struct FunctionResponse: Codable, Equatable, Sendable {
   let name: String
   let response: JSONObject
+  let id: String?
 
-  init(name: String, response: JSONObject) {
+  init(name: String, response: JSONObject, id: String?) {
     self.name = name
     self.response = response
+    self.id = id
   }
 }
 
@@ -79,6 +83,7 @@ extension FunctionCall: Codable {
   init(from decoder: Decoder) throws {
     let container = try decoder.container(keyedBy: CodingKeys.self)
     name = try container.decode(String.self, forKey: .name)
+    id = try container.decodeIfPresent(String.self, forKey: .id)
     if let args = try container.decodeIfPresent(JSONObject.self, forKey: .args) {
       self.args = args
     } else {
diff --git a/FirebaseAI/Sources/Types/Public/Part.swift b/FirebaseAI/Sources/Types/Public/Part.swift
index 4890b725f4d..1ec790f337d 100644
--- a/FirebaseAI/Sources/Types/Public/Part.swift
+++ b/FirebaseAI/Sources/Types/Public/Part.swift
@@ -112,6 +112,10 @@ public struct FunctionCallPart: Part {
   /// The function parameters and values.
   public var args: JSONObject { functionCall.args }
 
+  /// The unique ID of the function call. If specified, this identifier should be included in the
+  /// ``FunctionResponsePart``.
+  public var id: String? { functionCall.id }
+
   /// Constructs a new function call part.
   ///
   /// > Note: A `FunctionCallPart` is typically received from the model, rather than created
@@ -121,7 +125,7 @@ public struct FunctionCallPart: Part {
   ///   - name: The name of the function to call.
   ///   - args: The function parameters and values.
   public init(name: String, args: JSONObject) {
-    self.init(FunctionCall(name: name, args: args))
+    self.init(FunctionCall(name: name, args: args, id: nil))
   }
 
   init(_ functionCall: FunctionCall) {
@@ -149,8 +153,10 @@ public struct FunctionResponsePart: Part {
   /// - Parameters:
   ///   - name: The name of the function that was called.
   ///   - response: The function's response.
-  public init(name: String, response: JSONObject) {
-    self.init(FunctionResponse(name: name, response: response))
+  ///   - id: The unique ID of the function call, if specified, that this response corresponds with;
+  ///     see ``FunctionCallPart/id`` for more details.
+  public init(name: String, response: JSONObject, id: String? = nil) {
+    self.init(FunctionResponse(name: name, response: response, id: id))
   }
 
   init(_ functionResponse: FunctionResponse) {
diff --git a/FirebaseAI/Tests/Unit/Snippets/FunctionCallingSnippets.swift b/FirebaseAI/Tests/Unit/Snippets/FunctionCallingSnippets.swift
index e8ef9bf512c..e3264cc4e00 100644
--- a/FirebaseAI/Tests/Unit/Snippets/FunctionCallingSnippets.swift
+++ b/FirebaseAI/Tests/Unit/Snippets/FunctionCallingSnippets.swift
@@ -92,7 +92,8 @@ final class FunctionCallingSnippets: XCTestCase {
 
         functionResponses.append(FunctionResponsePart(
           name: functionCall.name,
-          response: fetchWeather(city: city, state: state, date: date)
+          response: fetchWeather(city: city, state: state, date: date),
+          id: functionCall.id
         ))
       }
       // TODO(developer): Handle other potential function calls, if any.