diff --git a/packages/react-scripts/config/env.js b/packages/react-scripts/config/env.js
index 66ba341b358..168e1e644f1 100644
--- a/packages/react-scripts/config/env.js
+++ b/packages/react-scripts/config/env.js
@@ -15,25 +15,33 @@
 var REACT_APP = /^REACT_APP_/i;
 
 function getClientEnvironment(publicUrl) {
-  var processEnv = Object
+  var raw = Object
     .keys(process.env)
     .filter(key => REACT_APP.test(key))
     .reduce((env, key) => {
-      env[key] = JSON.stringify(process.env[key]);
+      env[key] = process.env[key];
       return env;
     }, {
       // Useful for determining whether we’re running in production mode.
       // Most importantly, it switches React into the correct mode.
-      'NODE_ENV': JSON.stringify(
-        process.env.NODE_ENV || 'development'
-      ),
+      'NODE_ENV': process.env.NODE_ENV || 'development',
       // Useful for resolving the correct path to static assets in `public`.
       // For example, <img src={process.env.PUBLIC_URL + '/img/logo.png'} />.
       // This should only be used as an escape hatch. Normally you would put
       // images into the `src` and `import` them in code to get their paths.
-      'PUBLIC_URL': JSON.stringify(publicUrl)
+      'PUBLIC_URL': publicUrl
     });
-  return {'process.env': processEnv};
+  // Stringify all values so we can feed into Webpack DefinePlugin
+  var stringified = {
+    'process.env': Object
+      .keys(raw)
+      .reduce((env, key) => {
+        env[key] = JSON.stringify(raw[key]);
+        return env;
+      }, {})
+  };
+
+  return { raw, stringified };
 }
 
 module.exports = getClientEnvironment;
diff --git a/packages/react-scripts/config/webpack.config.dev.js b/packages/react-scripts/config/webpack.config.dev.js
index 96fd632b795..cbac62595b1 100644
--- a/packages/react-scripts/config/webpack.config.dev.js
+++ b/packages/react-scripts/config/webpack.config.dev.js
@@ -202,12 +202,11 @@ module.exports = {
     ];
   },
   plugins: [
-    // Makes the public URL available as %PUBLIC_URL% in index.html, e.g.:
+    // Makes some environment variables available in index.html.
+    // The public URL is available as %PUBLIC_URL% in index.html, e.g.:
     // <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
     // In development, this will be an empty string.
-    new InterpolateHtmlPlugin({
-      PUBLIC_URL: publicUrl
-    }),
+    new InterpolateHtmlPlugin(env.raw),
     // Generates an `index.html` file with the <script> injected.
     new HtmlWebpackPlugin({
       inject: true,
@@ -215,7 +214,7 @@ module.exports = {
     }),
     // Makes some environment variables available to the JS code, for example:
     // if (process.env.NODE_ENV === 'development') { ... }. See `./env.js`.
-    new webpack.DefinePlugin(env),
+    new webpack.DefinePlugin(env.stringified),
     // This is necessary to emit hot updates (currently CSS only):
     new webpack.HotModuleReplacementPlugin(),
     // Watcher doesn't work well if you mistype casing in a path so we use
diff --git a/packages/react-scripts/config/webpack.config.prod.js b/packages/react-scripts/config/webpack.config.prod.js
index 058db0d7921..544231bac34 100644
--- a/packages/react-scripts/config/webpack.config.prod.js
+++ b/packages/react-scripts/config/webpack.config.prod.js
@@ -54,7 +54,7 @@ var env = getClientEnvironment(publicUrl);
 
 // Assert this just to be safe.
 // Development builds of React are slow and not intended for production.
-if (env['process.env'].NODE_ENV !== '"production"') {
+if (env.stringified['process.env'].NODE_ENV !== '"production"') {
   throw new Error('Production builds must have NODE_ENV=production.');
 }
 
@@ -214,13 +214,12 @@ module.exports = {
     ];
   },
   plugins: [
-    // Makes the public URL available as %PUBLIC_URL% in index.html, e.g.:
+    // Makes some environment variables available in index.html.
+    // The public URL is available as %PUBLIC_URL% in index.html, e.g.:
     // <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
     // In production, it will be an empty string unless you specify "homepage"
     // in `package.json`, in which case it will be the pathname of that URL.
-    new InterpolateHtmlPlugin({
-      PUBLIC_URL: publicUrl
-    }),
+    new InterpolateHtmlPlugin(env.raw),
     // Generates an `index.html` file with the <script> injected.
     new HtmlWebpackPlugin({
       inject: true,
@@ -242,7 +241,7 @@ module.exports = {
     // if (process.env.NODE_ENV === 'production') { ... }. See `./env.js`.
     // It is absolutely essential that NODE_ENV was set to production here.
     // Otherwise React will be compiled in the very slow development mode.
-    new webpack.DefinePlugin(env),
+    new webpack.DefinePlugin(env.stringified),
     // This helps ensure the builds are consistent if source hasn't changed:
     new webpack.optimize.OccurrenceOrderPlugin(),
     // Try to dedupe duplicated modules, if any: