diff --git a/packages/babel-core/src/tools/build-external-helpers.js b/packages/babel-core/src/tools/build-external-helpers.js
index 057e4b69e9..063ad8a5be 100644
--- a/packages/babel-core/src/tools/build-external-helpers.js
+++ b/packages/babel-core/src/tools/build-external-helpers.js
@@ -74,9 +74,9 @@ function buildVar(namespace, builder) {
 
 function buildHelpers(body, namespace, whitelist) {
   each(helpers.list, function (name) {
-    if (whitelist && whitelist.indexOf(name) >= 0) return;
+    if (whitelist && whitelist.indexOf(name) < 0) return;
 
-    let key = t.identifier(t.toIdentifier(name));
+    let key = t.identifier(name);
     body.push(t.expressionStatement(
       t.assignmentExpression("=", t.memberExpression(namespace, key), helpers.get(name))
     ));
diff --git a/packages/babel-helpers/src/helpers.js b/packages/babel-helpers/src/helpers.js
index fc4b8ebbf2..6b081e8df2 100644
--- a/packages/babel-helpers/src/helpers.js
+++ b/packages/babel-helpers/src/helpers.js
@@ -1,12 +1,15 @@
 import template from "babel-template";
 
-export let _typeof = template(`
+let helpers = {};
+export default helpers;
+
+helpers.typeof = template(`
   (function (obj) {
     return obj && typeof Symbol !== "undefined" && obj.constructor === Symbol ? "symbol" : typeof obj;
   });
 `);
 
-export let createRawReactElement = template(`
+helpers.createRawReactElement = template(`
   (function () {
     var REACT_ELEMENT_TYPE = (typeof Symbol === "function" && Symbol.for && Symbol.for("react.element")) || 0xeac7;
 
@@ -24,7 +27,7 @@ export let createRawReactElement = template(`
   })()
 `);
 
-export let asyncToGenerator = template(`
+helpers.asyncToGenerator = template(`
   (function (fn) {
     return function () {
       var gen = fn.apply(this, arguments);
@@ -56,7 +59,7 @@ export let asyncToGenerator = template(`
 `);
 
 
-export let classCallCheck = template(`
+helpers.classCallCheck = template(`
   (function (instance, Constructor) {
     if (!(instance instanceof Constructor)) {
       throw new TypeError("Cannot call a class as a function");
@@ -64,7 +67,7 @@ export let classCallCheck = template(`
   });
 `);
 
-export let createClass = template(`
+helpers.createClass = template(`
   (function() {
     function defineProperties(target, props) {
       for (var i = 0; i < props.length; i ++) {
@@ -84,7 +87,7 @@ export let createClass = template(`
   })()
 `);
 
-export let defaultProps = template(`
+helpers.defaultProps = template(`
   (function (defaultProps, props) {
     if (defaultProps) {
       for (var propName in defaultProps) {
@@ -98,7 +101,7 @@ export let defaultProps = template(`
 `);
 
 
-export let defineEnumerableProperties = template(`
+helpers.defineEnumerableProperties = template(`
   (function (obj, descs) {
     for (var key in descs) {
       var desc = descs[key];
@@ -110,7 +113,7 @@ export let defineEnumerableProperties = template(`
   })
 `);
 
-export let defaults = template(`
+helpers.defaults = template(`
   (function (obj, defaults) {
     var keys = Object.getOwnPropertyNames(defaults);
     for (var i = 0; i < keys.length; i++) {
@@ -124,7 +127,7 @@ export let defaults = template(`
   })
 `);
 
-export let defineProperty = template(`
+helpers.defineProperty = template(`
   (function (obj, key, value) {
     // Shortcircuit the slow defineProperty path when possible.
     // We are trying to avoid issues where setters defined on the
@@ -145,7 +148,7 @@ export let defineProperty = template(`
   });
 `);
 
-export let _extends = template(`
+helpers.extends = template(`
   Object.assign || (function (target) {
     for (var i = 1; i < arguments.length; i++) {
       var source = arguments[i];
@@ -159,7 +162,7 @@ export let _extends = template(`
   })
 `);
 
-export let get = template(`
+helpers.get = template(`
   (function get(object, property, receiver) {
     if (object === null) object = Function.prototype;
 
@@ -188,7 +191,7 @@ export let get = template(`
 `);
 
 
-export let inherits = template(`
+helpers.inherits = template(`
   (function (subClass, superClass) {
     if (typeof superClass !== "function" && superClass !== null) {
       throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
@@ -205,7 +208,7 @@ export let inherits = template(`
   })
 `);
 
-export let _instanceof = template(`
+helpers.instanceof = template(`
   (function (left, right) {
     if (right != null && typeof Symbol !== "undefined" && right[Symbol.hasInstance]) {
       return right[Symbol.hasInstance](left);
@@ -216,13 +219,13 @@ export let _instanceof = template(`
 `);
 
 
-export let interopRequireDefault = template(`
+helpers.interopRequireDefault = template(`
   (function (obj) {
     return obj && obj.__esModule ? obj : { default: obj };
   })
 `);
 
-export let interopRequireWildcard = template(`
+helpers.interopRequireWildcard = template(`
   (function (obj) {
     if (obj && obj.__esModule) {
       return obj;
@@ -239,7 +242,7 @@ export let interopRequireWildcard = template(`
   })
 `);
 
-export let newArrowCheck = template(`
+helpers.newArrowCheck = template(`
   (function (innerThis, boundThis) {
     if (innerThis !== boundThis) {
       throw new TypeError("Cannot instantiate an arrow function");
@@ -247,13 +250,13 @@ export let newArrowCheck = template(`
   });
 `);
 
-export let objectDestructuringEmpty = template(`
+helpers.objectDestructuringEmpty = template(`
   (function (obj) {
     if (obj == null) throw new TypeError("Cannot destructure undefined");
   });
 `);
 
-export let objectWithoutProperties = template(`
+helpers.objectWithoutProperties = template(`
   (function (obj, keys) {
     var target = {};
     for (var i in obj) {
@@ -265,7 +268,7 @@ export let objectWithoutProperties = template(`
   })
 `);
 
-export let possibleConstructorReturn = template(`
+helpers.possibleConstructorReturn = template(`
   (function (self, call) {
     if (!self) {
       throw new ReferenceError("this hasn't been initialised - super() hasn't been called");
@@ -274,11 +277,11 @@ export let possibleConstructorReturn = template(`
   });
 `);
 
-export let selfGlobal = template(`
+helpers.selfGlobal = template(`
   typeof global === "undefined" ? self : global
 `);
 
-export let set = template(`
+helpers.set = template(`
   (function set(object, property, value, receiver) {
     var desc = Object.getOwnPropertyDescriptor(object, property);
 
@@ -302,7 +305,7 @@ export let set = template(`
   });
 `);
 
-export let slicedToArray = template(`
+helpers.slicedToArray = template(`
   (function () {
     // Broken out into a separate function to avoid deoptimizations due to the try/catch for the
     // array iterator case.
@@ -351,7 +354,7 @@ export let slicedToArray = template(`
   })();
 `);
 
-export let slicedToArrayLoose = template(`
+helpers.slicedToArrayLoose = template(`
   (function (arr, i) {
     if (Array.isArray(arr)) {
       return arr;
@@ -368,7 +371,7 @@ export let slicedToArrayLoose = template(`
   });
 `);
 
-export let taggedTemplateLiteral = template(`
+helpers.taggedTemplateLiteral = template(`
   (function (strings, raw) {
     return Object.freeze(Object.defineProperties(strings, {
         raw: { value: Object.freeze(raw) }
@@ -376,14 +379,14 @@ export let taggedTemplateLiteral = template(`
   });
 `);
 
-export let taggedTemplateLiteralLoose = template(`
+helpers.taggedTemplateLiteralLoose = template(`
   (function (strings, raw) {
     strings.raw = raw;
     return strings;
   });
 `);
 
-export let temporalRef = template(`
+helpers.temporalRef = template(`
   (function (val, name, undef) {
     if (val === undef) {
       throw new ReferenceError(name + " is not defined - temporal dead zone");
@@ -393,17 +396,17 @@ export let temporalRef = template(`
   })
 `);
 
-export let temporalUndefined = template(`
+helpers.temporalUndefined = template(`
   ({})
 `);
 
-export let toArray = template(`
+helpers.toArray = template(`
   (function (arr) {
     return Array.isArray(arr) ? arr : Array.from(arr);
   });
 `);
 
-export let toConsumableArray = template(`
+helpers.toConsumableArray = template(`
   (function (arr) {
     if (Array.isArray(arr)) {
       for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) arr2[i] = arr[i];
diff --git a/packages/babel-helpers/src/index.js b/packages/babel-helpers/src/index.js
index 46fb1080e0..96a5b4cb10 100644
--- a/packages/babel-helpers/src/index.js
+++ b/packages/babel-helpers/src/index.js
@@ -1,7 +1,7 @@
-import * as helpers from "./helpers";
+import helpers from "./helpers";
 
 export function get(name) {
-  let fn = helpers[name] || helpers[`_${name}`];
+  let fn = helpers[name];
   if (!fn) throw ReferenceError;
 
   return fn().expression;
diff --git a/packages/babel-plugin-transform-es2015-instanceof/test/fixtures/instanceof/instanceof/expected.js b/packages/babel-plugin-transform-es2015-instanceof/test/fixtures/instanceof/instanceof/expected.js
index 5991efed09..1772fba566 100644
--- a/packages/babel-plugin-transform-es2015-instanceof/test/fixtures/instanceof/instanceof/expected.js
+++ b/packages/babel-plugin-transform-es2015-instanceof/test/fixtures/instanceof/instanceof/expected.js
@@ -1 +1 @@
-babelHelpers._instanceof(a, b);
+babelHelpers.instanceof(a, b);
diff --git a/packages/babel-plugin-transform-es2015-typeof-symbol/test/fixtures/symbols/typeof/expected.js b/packages/babel-plugin-transform-es2015-typeof-symbol/test/fixtures/symbols/typeof/expected.js
index 50931cbb5f..26a766f3d5 100644
--- a/packages/babel-plugin-transform-es2015-typeof-symbol/test/fixtures/symbols/typeof/expected.js
+++ b/packages/babel-plugin-transform-es2015-typeof-symbol/test/fixtures/symbols/typeof/expected.js
@@ -1,5 +1,5 @@
 var s = Symbol("s");
-assert.ok((typeof s === "undefined" ? "undefined" : babelHelpers._typeof(s)) === "symbol");
-assert.equal(typeof s === "undefined" ? "undefined" : babelHelpers._typeof(s), "symbol");
-assert.equal(babelHelpers._typeof(babelHelpers._typeof(s.foo)), "symbol");
+assert.ok((typeof s === "undefined" ? "undefined" : babelHelpers.typeof(s)) === "symbol");
+assert.equal(typeof s === "undefined" ? "undefined" : babelHelpers.typeof(s), "symbol");
+assert.equal(babelHelpers.typeof(babelHelpers.typeof(s.foo)), "symbol");
 typeof s === "string";
diff --git a/packages/babel-plugin-transform-proto-to-assign/test/fixtures/proto-to-assign/object-literal/expected.js b/packages/babel-plugin-transform-proto-to-assign/test/fixtures/proto-to-assign/object-literal/expected.js
index 66c96c814c..d1a37e69a3 100644
--- a/packages/babel-plugin-transform-proto-to-assign/test/fixtures/proto-to-assign/object-literal/expected.js
+++ b/packages/babel-plugin-transform-proto-to-assign/test/fixtures/proto-to-assign/object-literal/expected.js
@@ -1,9 +1,9 @@
-var foo = babelHelpers._extends({}, bar);
+var foo = babelHelpers.extends({}, bar);
 
-var foo = babelHelpers._extends({}, bar, {
+var foo = babelHelpers.extends({}, bar, {
   bar: "foo"
 });
 
-var foo = babelHelpers._extends({}, bar, {
+var foo = babelHelpers.extends({}, bar, {
   bar: "foo"
 });
diff --git a/packages/babel-plugin-transform-react-jsx/test/fixtures/react/adds-appropriate-newlines-when-using-spread-attribute/expected.js b/packages/babel-plugin-transform-react-jsx/test/fixtures/react/adds-appropriate-newlines-when-using-spread-attribute/expected.js
index 6b53e13c76..4f77e7827b 100644
--- a/packages/babel-plugin-transform-react-jsx/test/fixtures/react/adds-appropriate-newlines-when-using-spread-attribute/expected.js
+++ b/packages/babel-plugin-transform-react-jsx/test/fixtures/react/adds-appropriate-newlines-when-using-spread-attribute/expected.js
@@ -1,2 +1,2 @@
-React.createElement(Component, babelHelpers._extends({}, props, {
+React.createElement(Component, babelHelpers.extends({}, props, {
   sound: "moo" }));
diff --git a/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-first-spread-attributes/expected.js b/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-first-spread-attributes/expected.js
index 1f73d98596..9e45d91cee 100644
--- a/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-first-spread-attributes/expected.js
+++ b/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-first-spread-attributes/expected.js
@@ -1 +1 @@
-React.createElement(Component, babelHelpers._extends({}, x, { y: 2, z: true }));
+React.createElement(Component, babelHelpers.extends({}, x, { y: 2, z: true }));
diff --git a/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-last-spread-attributes/expected.js b/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-last-spread-attributes/expected.js
index f4d1b0c28a..893deb2dba 100644
--- a/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-last-spread-attributes/expected.js
+++ b/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-last-spread-attributes/expected.js
@@ -1 +1 @@
-React.createElement(Component, babelHelpers._extends({ y: 2, z: true }, x));
+React.createElement(Component, babelHelpers.extends({ y: 2, z: true }, x));
diff --git a/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-middle-spread-attributes/expected.js b/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-middle-spread-attributes/expected.js
index 47b25a627b..88573fe613 100644
--- a/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-middle-spread-attributes/expected.js
+++ b/packages/babel-plugin-transform-react-jsx/test/fixtures/react/wraps-props-in-react-spread-for-middle-spread-attributes/expected.js
@@ -1 +1 @@
-React.createElement(Component, babelHelpers._extends({ y: 2 }, x, { z: true }));
+React.createElement(Component, babelHelpers.extends({ y: 2 }, x, { z: true }));
diff --git a/packages/babel-runtime/scripts/build-dist.js b/packages/babel-runtime/scripts/build-dist.js
index c07a62fe7b..8df84595e3 100644
--- a/packages/babel-runtime/scripts/build-dist.js
+++ b/packages/babel-runtime/scripts/build-dist.js
@@ -1,6 +1,7 @@
 var outputFile = require("output-file-sync");
 var each       = require("lodash/collection/each");
 var fs         = require("fs");
+var _          = require("lodash");
 
 var coreDefinitions = require("babel-plugin-transform-runtime").definitions;
 
@@ -84,6 +85,11 @@ function buildHelper(helperName) {
 
 each(helpers.list, function (helperName) {
   writeFile("helpers/" + helperName + ".js", buildHelper(helperName));
+
+  // compat
+  var helperAlias = _.kebabCase(helperName);
+  writeFile("helpers/_" + helperAlias + ".js", buildHelper(helperName));
+  writeFile("helpers/" + helperAlias + ".js", buildHelper(helperName));
 });
 
 writeFile("regenerator/index.js", readFile("regenerator/runtime-module", true));