diff --git a/src/vs/workbench/api/common/extHostWebview.ts b/src/vs/workbench/api/common/extHostWebview.ts
index e5dc3c670d5..1411775a7a8 100644
--- a/src/vs/workbench/api/common/extHostWebview.ts
+++ b/src/vs/workbench/api/common/extHostWebview.ts
@@ -54,6 +54,8 @@ export class ExtHostWebview implements vscode.Webview {
 	/* internal */ readonly _onDidDispose: Event<void> = this.#onDidDisposeEmitter.event;
 
 	public dispose() {
+		this.#isDisposed = true;
+
 		this.#onDidDisposeEmitter.fire();
 
 		this.#onDidDisposeEmitter.dispose();
@@ -99,8 +101,10 @@ export class ExtHostWebview implements vscode.Webview {
 		this.#options = newOptions;
 	}
 
-	public postMessage(message: any): Promise<boolean> {
-		this.assertNotDisposed();
+	public async postMessage(message: any): Promise<boolean> {
+		if (this.#isDisposed) {
+			return false;
+		}
 		return this.#proxy.$postMessage(this.#handle, message);
 	}
 
diff --git a/src/vs/workbench/api/common/extHostWebviewView.ts b/src/vs/workbench/api/common/extHostWebviewView.ts
index 9cbff1880d5..a9f3db59641 100644
--- a/src/vs/workbench/api/common/extHostWebviewView.ts
+++ b/src/vs/workbench/api/common/extHostWebviewView.ts
@@ -51,6 +51,8 @@ class ExtHostWebviewView extends Disposable implements vscode.WebviewView {
 		this.#isDisposed = true;
 		this.#onDidDispose.fire();
 
+		this.#webview.dispose();
+
 		super.dispose();
 	}
 
@@ -186,6 +188,8 @@ export class ExtHostWebviewViews implements extHostProtocol.ExtHostWebviewViewsS
 		const webviewView = this.getWebviewView(webviewHandle);
 		this._webviewViews.delete(webviewHandle);
 		webviewView.dispose();
+
+		this._extHostWebview.deleteWebview(webviewHandle);
 	}
 
 	private getWebviewView(handle: string): ExtHostWebviewView {
diff --git a/src/vs/workbench/contrib/webviewView/browser/webviewViewPane.ts b/src/vs/workbench/contrib/webviewView/browser/webviewViewPane.ts
index 8e2849173f7..c4b7399bdff 100644
--- a/src/vs/workbench/contrib/webviewView/browser/webviewViewPane.ts
+++ b/src/vs/workbench/contrib/webviewView/browser/webviewViewPane.ts
@@ -89,6 +89,8 @@ export class WebviewViewPane extends ViewPane {
 	dispose() {
 		this._onDispose.fire();
 
+		this._webview?.dispose();
+
 		super.dispose();
 	}