diff --git a/src/Umbraco.Web.UI.Client/src/packages/templating/stylesheets/repository/stylesheet-detail.server.data-source.ts b/src/Umbraco.Web.UI.Client/src/packages/templating/stylesheets/repository/stylesheet-detail.server.data-source.ts
index 27c5ef74a8..f740f44d5e 100644
--- a/src/Umbraco.Web.UI.Client/src/packages/templating/stylesheets/repository/stylesheet-detail.server.data-source.ts
+++ b/src/Umbraco.Web.UI.Client/src/packages/templating/stylesheets/repository/stylesheet-detail.server.data-source.ts
@@ -41,7 +41,7 @@ export class UmbStylesheetDetailServerDataSource implements UmbDetailDataSource<
 		// TODO: make data mapper to prevent errors
 		const requestBody: CreateStylesheetRequestModel = {
 			parentPath,
-			name: appendFileExtensionIfNeeded(stylesheet.name, '.js'),
+			name: appendFileExtensionIfNeeded(stylesheet.name, '.css'),
 			content: stylesheet.content,
 		};