diff --git a/packages/rollup-plugin-babel/src/index.js b/packages/rollup-plugin-babel/src/index.js
index 315e69b6f..50bc6fdda 100644
--- a/packages/rollup-plugin-babel/src/index.js
+++ b/packages/rollup-plugin-babel/src/index.js
@@ -1,8 +1,9 @@
 import { dirname } from 'path';
 import { buildExternalHelpers, transform } from 'babel-core';
 import { createFilter } from 'rollup-pluginutils';
+import assign from 'object-assign';
 import preflightCheck from './preflightCheck.js';
-import { assign, warnOnce } from './utils.js';
+import { warnOnce } from './utils.js';
 import { RUNTIME, BUNDLED, HELPERS } from './constants.js';
 
 const keywordHelpers = [ 'typeof', 'extends', 'instanceof' ];
diff --git a/packages/rollup-plugin-babel/src/preflightCheck.js b/packages/rollup-plugin-babel/src/preflightCheck.js
index 56cc9f5a5..38d0554f6 100644
--- a/packages/rollup-plugin-babel/src/preflightCheck.js
+++ b/packages/rollup-plugin-babel/src/preflightCheck.js
@@ -1,5 +1,5 @@
 import { join } from 'path';
-import { assign } from './utils.js';
+import assign from 'object-assign';
 import { transform } from 'babel-core';
 import { INLINE, RUNTIME, BUNDLED } from './constants.js';
 import classes from 'babel-plugin-transform-es2015-classes';
diff --git a/packages/rollup-plugin-babel/src/utils.js b/packages/rollup-plugin-babel/src/utils.js
index f4cfbb6b1..5ed0f876c 100644
--- a/packages/rollup-plugin-babel/src/utils.js
+++ b/packages/rollup-plugin-babel/src/utils.js
@@ -1,10 +1,3 @@
-export function assign ( target, source ) {
-	Object.keys( source ).forEach( key => {
-		target[ key ] = source[ key ];
-	});
-	return target;
-}
-
 let warned = {};
 export function warnOnce ( warn, msg ) {
 	if ( warned[ msg ] ) return;