diff --git a/src/vs/base/test/common/resources.test.ts b/src/vs/base/test/common/resources.test.ts
index 5fdf1ba1088..b45ea4fc2f8 100644
--- a/src/vs/base/test/common/resources.test.ts
+++ b/src/vs/base/test/common/resources.test.ts
@@ -108,6 +108,7 @@ suite('Resources', () => {
 			assert.equal(joinPath(URI.file('/foo/bar'), '/./file.js').toString(), 'file:///foo/bar/file.js');
 			assert.equal(joinPath(URI.file('/foo/bar'), '../file.js').toString(), 'file:///foo/file.js');
 		}
+		assert.equal(joinPath(URI.parse('foo://a/foo/bar')).toString(), 'foo://a/foo/bar');
 		assert.equal(joinPath(URI.parse('foo://a/foo/bar'), '/file.js').toString(), 'foo://a/foo/bar/file.js');
 		assert.equal(joinPath(URI.parse('foo://a/foo/bar'), 'file.js').toString(), 'foo://a/foo/bar/file.js');
 		assert.equal(joinPath(URI.parse('foo://a/foo/bar/'), '/file.js').toString(), 'foo://a/foo/bar/file.js');
diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index af1c5911586..f62ac3337db 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -1643,5 +1643,15 @@ declare module 'vscode' {
 		asExtensionUri(relativePath: string): Uri;
 	}
 
+	export interface Extension<T> {
+		/**
+		 * Get the uri of a resource contained in the extension.
+		 *
+		 * @param relativePath A relative path to a resource contained in the extension.
+		 * @return The uri of the resource.
+		 */
+		asExtensionUri(relativePath: string): Uri;
+	}
+
 	//#endregion
 }
diff --git a/src/vs/workbench/api/common/extHost.api.impl.ts b/src/vs/workbench/api/common/extHost.api.impl.ts
index 01e6949541c..f8382ef8b10 100644
--- a/src/vs/workbench/api/common/extHost.api.impl.ts
+++ b/src/vs/workbench/api/common/extHost.api.impl.ts
@@ -53,7 +53,7 @@ import { ProxyIdentifier } from 'vs/workbench/services/extensions/common/proxyId
 import { ExtensionDescriptionRegistry } from 'vs/workbench/services/extensions/common/extensionDescriptionRegistry';
 import * as vscode from 'vscode';
 import { ExtensionIdentifier, IExtensionDescription } from 'vs/platform/extensions/common/extensions';
-import { originalFSPath } from 'vs/base/common/resources';
+import { originalFSPath, joinPath } from 'vs/base/common/resources';
 import { values } from 'vs/base/common/collections';
 import { ExtHostEditorInsets } from 'vs/workbench/api/common/extHostCodeInsets';
 import { ExtHostLabelService } from 'vs/workbench/api/common/extHostLabelService';
@@ -1020,6 +1020,11 @@ class Extension<T> implements vscode.Extension<T> {
 		this.extensionKind = kind;
 	}
 
+	asExtensionUri(relativePath: string): URI {
+		checkProposedApiEnabled(this.packageJSON);
+		return joinPath(this.packageJSON.extensionLocation, relativePath);
+	}
+
 	get isActive(): boolean {
 		return this._extensionService.isActivated(this._identifier);
 	}