diff --git a/src/vs/base/browser/ui/list/listView.ts b/src/vs/base/browser/ui/list/listView.ts
index d2678253ecdc9710c102f7bf0461c5e78ed41feb..d42777bec4b2b306f98b969fee09df541cdbd6c8 100644
--- a/src/vs/base/browser/ui/list/listView.ts
+++ b/src/vs/base/browser/ui/list/listView.ts
@@ -571,7 +571,7 @@ export class ListView<T> implements ISpliceable<T>, IDisposable {
 			const role = this.ariaProvider.getRole ? this.ariaProvider.getRole(item.element) : 'treeitem';
 			item.row!.domNode!.setAttribute('role', role);
 			const checked = this.ariaProvider.isChecked ? this.ariaProvider.isChecked(item.element) : undefined;
-			if (checked !== undefined) {
+			if (typeof checked !== 'undefined') {
 				item.row!.domNode!.setAttribute('aria-checked', String(checked));
 			}
 		}