diff --git a/src/integrations/terminal/Terminal.ts b/src/integrations/terminal/Terminal.ts
index 8bf2072f3d..bfeae3e8f8 100644
--- a/src/integrations/terminal/Terminal.ts
+++ b/src/integrations/terminal/Terminal.ts
@@ -157,6 +157,12 @@ export class Terminal extends BaseTerminal {
 			// VTE must be disabled because it prevents the prompt command from executing
 			// See https://wiki.gnome.org/Apps/Terminal/VTE
 			VTE_VERSION: "0",
+
+			// Ensure UTF-8 encoding for proper Unicode character display
+			// This fixes issues with non-ASCII characters (Cyrillic, Chinese, Hindi, etc.)
+			// being displayed as "?" or diamond symbols in terminal output
+			LANG: "en_US.UTF-8",
+			LC_ALL: "en_US.UTF-8",
 		}
 
 		// Set Oh My Zsh shell integration if enabled
diff --git a/src/integrations/terminal/TerminalProcess.ts b/src/integrations/terminal/TerminalProcess.ts
index eb0424fe8d..fe45f2f427 100644
--- a/src/integrations/terminal/TerminalProcess.ts
+++ b/src/integrations/terminal/TerminalProcess.ts
@@ -114,9 +114,21 @@ export class TerminalProcess extends BaseTerminalProcess {
 			(defaultWindowsShellProfile === null ||
 				(defaultWindowsShellProfile as string)?.toLowerCase().includes("powershell"))
 
-		if (isPowerShell) {
-			let commandToExecute = command
+		let commandToExecute = command
+
+		// On Windows, prepend chcp 65001 to set UTF-8 code page for proper Unicode support
+		// This fixes issues with non-ASCII characters being displayed as "?" or diamond symbols
+		if (process.platform === "win32") {
+			if (isPowerShell) {
+				// PowerShell syntax: use semicolon to chain commands and redirect output to null
+				commandToExecute = `chcp 65001 > $null ; ${command}`
+			} else {
+				// CMD syntax: use && to chain commands and redirect output to nul
+				commandToExecute = `chcp 65001 > nul && ${command}`
+			}
+		}
 
+		if (isPowerShell) {
 			// Only add the PowerShell counter workaround if enabled
 			if (Terminal.getPowershellCounter()) {
 				commandToExecute += ` ; "(Roo/PS Workaround: ${this.terminal.cmdCounter++})" > $null`
@@ -126,12 +138,10 @@ export class TerminalProcess extends BaseTerminalProcess {
 			if (Terminal.getCommandDelay() > 0) {
 				commandToExecute += ` ; start-sleep -milliseconds ${Terminal.getCommandDelay()}`
 			}
-
-			terminal.shellIntegration.executeCommand(commandToExecute)
-		} else {
-			terminal.shellIntegration.executeCommand(command)
 		}
 
+		terminal.shellIntegration.executeCommand(commandToExecute)
+
 		this.isHot = true
 
 		// Wait for stream to be available
diff --git a/src/integrations/terminal/__tests__/TerminalRegistry.spec.ts b/src/integrations/terminal/__tests__/TerminalRegistry.spec.ts
index d3912caf47..657433f23a 100644
--- a/src/integrations/terminal/__tests__/TerminalRegistry.spec.ts
+++ b/src/integrations/terminal/__tests__/TerminalRegistry.spec.ts
@@ -48,6 +48,8 @@ describe("TerminalRegistry", () => {
 					PAGER,
 					VTE_VERSION: "0",
 					PROMPT_EOL_MARK: "",
+					LANG: "en_US.UTF-8",
+					LC_ALL: "en_US.UTF-8",
 				},
 			})
 		})
@@ -69,6 +71,8 @@ describe("TerminalRegistry", () => {
 						PROMPT_COMMAND: "sleep 0.05",
 						VTE_VERSION: "0",
 						PROMPT_EOL_MARK: "",
+						LANG: "en_US.UTF-8",
+						LC_ALL: "en_US.UTF-8",
 					},
 				})
 			} finally {
@@ -91,6 +95,8 @@ describe("TerminalRegistry", () => {
 						VTE_VERSION: "0",
 						PROMPT_EOL_MARK: "",
 						ITERM_SHELL_INTEGRATION_INSTALLED: "Yes",
+						LANG: "en_US.UTF-8",
+						LC_ALL: "en_US.UTF-8",
 					},
 				})
 			} finally {
@@ -112,6 +118,8 @@ describe("TerminalRegistry", () => {
 						VTE_VERSION: "0",
 						PROMPT_EOL_MARK: "",
 						POWERLEVEL9K_TERM_SHELL_INTEGRATION: "true",
+						LANG: "en_US.UTF-8",
+						LC_ALL: "en_US.UTF-8",
 					},
 				})
 			} finally {