diff --git a/src/vs/platform/extensions/common/extensionsRegistry.ts b/src/vs/platform/extensions/common/extensionsRegistry.ts
index 24d54d6907b..fd969d13623 100644
--- a/src/vs/platform/extensions/common/extensionsRegistry.ts
+++ b/src/vs/platform/extensions/common/extensionsRegistry.ts
@@ -11,6 +11,7 @@ import Severity from 'vs/base/common/severity';
 import { IMessage, IExtensionDescription } from 'vs/platform/extensions/common/extensions';
 import { Extensions, IJSONContributionRegistry } from 'vs/platform/jsonschemas/common/jsonContributionRegistry';
 import { Registry } from 'vs/platform/registry/common/platform';
+import { EXTENSION_IDENTIFIER_PATTERN } from 'vs/platform/extensionManagement/common/extensionManagement';
 
 const hasOwnProperty = Object.hasOwnProperty;
 const schemaRegistry = <IJSONContributionRegistry>Registry.as(Extensions.JSONContribution);
@@ -243,7 +244,8 @@ const schema: IJSONSchema = {
 			type: 'array',
 			uniqueItems: true,
 			items: {
-				type: 'string'
+				type: 'string',
+				pattern: EXTENSION_IDENTIFIER_PATTERN
 			}
 		},
 		scripts: {