diff --git a/src/vs/workbench/contrib/comments/common/commentModel.ts b/src/vs/workbench/contrib/comments/common/commentModel.ts
index a9c9fbf27ec..4986e959ffe 100644
--- a/src/vs/workbench/contrib/comments/common/commentModel.ts
+++ b/src/vs/workbench/contrib/comments/common/commentModel.ts
@@ -6,7 +6,7 @@
 import { URI } from 'vs/base/common/uri';
 import { IRange } from 'vs/editor/common/core/range';
 import { Comment, CommentThread, CommentThreadChangedEvent } from 'vs/editor/common/languages';
-import { groupBy, flatten } from 'vs/base/common/arrays';
+import { groupBy } from 'vs/base/common/arrays';
 import { localize } from 'vs/nls';
 
 export interface ICommentThreadChangedEvent extends CommentThreadChangedEvent {
@@ -71,9 +71,16 @@ export class CommentsModel {
 		this.commentThreadsMap = new Map<string, ResourceWithCommentThreads[]>();
 	}
 
+	private updateResourceCommentThreads() {
+		this.resourceCommentThreads = [...this.commentThreadsMap.values()].flat();
+		this.resourceCommentThreads.sort((a, b) => {
+			return a.resource.toString() > b.resource.toString() ? 1 : -1;
+		});
+	}
+
 	public setCommentThreads(owner: string, commentThreads: CommentThread[]): void {
 		this.commentThreadsMap.set(owner, this.groupByResource(owner, commentThreads));
-		this.resourceCommentThreads = flatten([...this.commentThreadsMap.values()]);
+		this.updateResourceCommentThreads();
 	}
 
 	public updateCommentThreads(event: ICommentThreadChangedEvent): boolean {
@@ -123,7 +130,7 @@ export class CommentsModel {
 		});
 
 		this.commentThreadsMap.set(owner, threadsForOwner);
-		this.resourceCommentThreads = flatten([...this.commentThreadsMap.values()]);
+		this.updateResourceCommentThreads();
 
 		return removed.length > 0 || changed.length > 0 || added.length > 0;
 	}