diff --git a/packages/base/src/index.ts b/packages/base/src/index.ts
index ba598611f5..da3b4b8514 100644
--- a/packages/base/src/index.ts
+++ b/packages/base/src/index.ts
@@ -13,8 +13,8 @@ governing permissions and limitations under the License.
 export * from './Base.js';
 export * from 'lit-element';
 export { nothing } from 'lit-html';
-export { ifDefined } from 'lit-html/directives/if-defined';
-export { repeat } from 'lit-html/directives/repeat';
-export { classMap } from 'lit-html/directives/class-map';
-export { styleMap } from 'lit-html/directives/style-map';
-export { until } from 'lit-html/directives/until';
+export { ifDefined } from 'lit-html/directives/if-defined.js';
+export { repeat } from 'lit-html/directives/repeat.js';
+export { classMap } from 'lit-html/directives/class-map.js';
+export { styleMap } from 'lit-html/directives/style-map.js';
+export { until } from 'lit-html/directives/until.js';