diff --git a/src/vs/workbench/api/browser/mainThreadLanguageModels.ts b/src/vs/workbench/api/browser/mainThreadLanguageModels.ts
index db30c270ad91c..1f952e1c0e653 100644
--- a/src/vs/workbench/api/browser/mainThreadLanguageModels.ts
+++ b/src/vs/workbench/api/browser/mainThreadLanguageModels.ts
@@ -26,6 +26,27 @@ import { SerializableObjectWithBuffers } from '../../services/extensions/common/
 import { ExtHostContext, ExtHostLanguageModelsShape, MainContext, MainThreadLanguageModelsShape } from '../common/extHost.protocol.js';
 import { LanguageModelError } from '../common/extHostTypes.js';
 
+class RequestCancellationTokenSource extends Disposable {
+
+	private readonly _source: CancellationTokenSource;
+
+	constructor(parent: CancellationToken, onCancellationRequested?: () => void) {
+		super();
+		this._source = this._register(new CancellationTokenSource(parent));
+		if (onCancellationRequested) {
+			this._register(this._source.token.onCancellationRequested(onCancellationRequested));
+		}
+	}
+
+	get token(): CancellationToken {
+		return this._source.token;
+	}
+
+	cancel(): void {
+		this._source.cancel();
+	}
+}
+
 @extHostNamedCustomer(MainContext.MainThreadLanguageModels)
 export class MainThreadLanguageModels implements MainThreadLanguageModelsShape {
 
@@ -34,7 +55,7 @@ export class MainThreadLanguageModels implements MainThreadLanguageModelsShape {
 	private readonly _providerRegistrations = new DisposableMap<string>();
 	private readonly _lmProviderChange = new Emitter<{ vendor: string }>();
 	private readonly _pendingProgress = new Map<number, { defer: DeferredPromise<unknown>; stream: AsyncIterableSource<IChatResponsePart | IChatResponsePart[]> }>();
-	private readonly _pendingCancelCTS = new DisposableMap<number, CancellationTokenSource>();
+	private readonly _pendingCancelCTS = new DisposableMap<number, RequestCancellationTokenSource>();
 	private readonly _ignoredFileProviderRegistrations = new DisposableMap<number>();
 
 	constructor(
@@ -100,11 +121,10 @@ export class MainThreadLanguageModels implements MainThreadLanguageModelsShape {
 					try {
 						this._pendingProgress.set(requestId, { defer, stream });
 
-						const cts = new CancellationTokenSource(token);
-						this._pendingCancelCTS.set(requestId, cts);
-						cts.token.onCancellationRequested(() => {
+						const cts = new RequestCancellationTokenSource(token, () => {
 							this._proxy.$cancelLanguageModelChatRequest(requestId);
 						});
+						this._pendingCancelCTS.set(requestId, cts);
 
 						await Promise.all(
 							messages.flatMap(msg => msg.content)
@@ -194,7 +214,7 @@ export class MainThreadLanguageModels implements MainThreadLanguageModelsShape {
 		// Create a local CTS so cancellation can be signalled via
 		// $cancelLanguageModelChatRequest even after the RPC cancel
 		// handler for the original token has been removed.
-		const cts = new CancellationTokenSource(token);
+		const cts = new RequestCancellationTokenSource(token);
 		this._pendingCancelCTS.set(requestId, cts);
 
 		let response: ILanguageModelChatResponse;
diff --git a/src/vs/workbench/api/test/browser/mainThreadLanguageModels.test.ts b/src/vs/workbench/api/test/browser/mainThreadLanguageModels.test.ts
index eb78b2c4f9633..9c15b812ccf2a 100644
--- a/src/vs/workbench/api/test/browser/mainThreadLanguageModels.test.ts
+++ b/src/vs/workbench/api/test/browser/mainThreadLanguageModels.test.ts
@@ -6,7 +6,7 @@
 import assert from 'assert';
 import { CancellationToken, CancellationTokenSource } from '../../../../base/common/cancellation.js';
 import { Emitter } from '../../../../base/common/event.js';
-import { DisposableStore } from '../../../../base/common/lifecycle.js';
+import { Disposable, DisposableStore } from '../../../../base/common/lifecycle.js';
 import { ExtensionIdentifier } from '../../../../platform/extensions/common/extensions.js';
 import { mock } from '../../../../base/test/common/mock.js';
 import { ensureNoDisposablesAreLeakedInTestSuite } from '../../../../base/test/common/utils.js';
@@ -14,7 +14,7 @@ import { NullLogService } from '../../../../platform/log/common/log.js';
 import { IAuthenticationService } from '../../../services/authentication/common/authentication.js';
 import { IAuthenticationAccessService } from '../../../services/authentication/browser/authenticationAccessService.js';
 import { ILanguageModelIgnoredFilesService } from '../../../contrib/chat/common/ignoredFiles.js';
-import { ILanguageModelsService, IChatMessage } from '../../../contrib/chat/common/languageModels.js';
+import { ILanguageModelChatProvider, ILanguageModelsService, IChatMessage } from '../../../contrib/chat/common/languageModels.js';
 import { SerializableObjectWithBuffers } from '../../../services/extensions/common/proxyIdentifier.js';
 import { TestExtensionService } from '../../../test/common/workbenchTestServices.js';
 import { MainThreadLanguageModels } from '../../browser/mainThreadLanguageModels.js';
@@ -165,4 +165,46 @@ suite('MainThreadLanguageModels', function () {
 		// Should not throw
 		mainThread.$cancelLanguageModelChatRequest(999999);
 	});
+
+	test('disposes the provider request cancellation listener when the response completes', async () => {
+		const store = disposables.add(new DisposableStore());
+		let provider: ILanguageModelChatProvider | undefined;
+		let requestId: number | undefined;
+		let cancelCount = 0;
+		const proxy: Partial<ExtHostLanguageModelsShape> = {
+			$startChatRequest: async (_modelId, id) => {
+				requestId = id;
+			},
+			$cancelLanguageModelChatRequest: () => {
+				cancelCount++;
+			},
+		};
+		const languageModelsService = new class extends mock<ILanguageModelsService>() {
+			override readonly onDidChangeLanguageModels = store.add(new Emitter<string>()).event;
+			override getLanguageModelIds(): string[] { return []; }
+			override registerLanguageModelProvider(_vendor: string, value: ILanguageModelChatProvider) {
+				provider = value;
+				return Disposable.None;
+			}
+		};
+
+		const mainThread = store.add(new MainThreadLanguageModels(
+			SingleProxyRPCProtocol(proxy),
+			languageModelsService,
+			new NullLogService(),
+			new class extends mock<IAuthenticationService>() { },
+			new class extends mock<IAuthenticationAccessService>() { },
+			new TestExtensionService(),
+			new class extends mock<ILanguageModelIgnoredFilesService>() { },
+		));
+		mainThread.$registerLanguageModelProvider('test');
+
+		const cts = store.add(new CancellationTokenSource());
+		const response = await provider!.sendChatRequest('model-1', [], undefined, {}, cts.token);
+		await mainThread.$reportResponseDone(requestId!, undefined);
+		await response.result;
+		cts.cancel();
+
+		assert.strictEqual(cancelCount, 0);
+	});
 });
diff --git a/src/vs/workbench/services/host/browser/toasts.ts b/src/vs/workbench/services/host/browser/toasts.ts
index fcec62cf82a4c..32c8e6d532303 100644
--- a/src/vs/workbench/services/host/browser/toasts.ts
+++ b/src/vs/workbench/services/host/browser/toasts.ts
@@ -43,9 +43,9 @@ export async function showBrowserToast(controller: IShowToastController, options
 
 		disposables.add(cts.token.onCancellationRequested(() => resolve({ supported: true, clicked: false })));
 
-		Event.once(toast.onClick)(() => resolve({ supported: true, clicked: true }));
-		Event.once(toast.onClose)(() => resolve({ supported: true, clicked: false }));
-		Event.once(toast.onError)(() => resolve({ supported: false, clicked: false }));
+		disposables.add(Event.once(toast.onClick)(() => resolve({ supported: true, clicked: true })));
+		disposables.add(Event.once(toast.onClose)(() => resolve({ supported: true, clicked: false })));
+		disposables.add(Event.once(toast.onError)(() => resolve({ supported: false, clicked: false })));
 	});
 }