diff --git a/Gulpfile.js b/Gulpfile.js
index eeec97362bfd..28f016f6c982 100644
--- a/Gulpfile.js
+++ b/Gulpfile.js
@@ -110,7 +110,7 @@ if (process.env.CIRCLE_PR_NUMBER) {
 
 const babelVersion =
   require("./packages/babel-core/package.json").version + versionSuffix;
-function buildRollup(packages) {
+function buildRollup(packages, targetBrowsers) {
   const sourcemap = process.env.NODE_ENV === "production";
   return Promise.all(
     packages.map(async ({ src, format, dest, name, filename }) => {
@@ -166,11 +166,12 @@ function buildRollup(packages) {
             ],
           }),
           rollupJson(),
-          rollupNodePolyfills({
-            sourceMap: sourcemap,
-            include: "**/*.{js,ts}",
-          }),
-        ],
+          targetBrowsers &&
+            rollupNodePolyfills({
+              sourceMap: sourcemap,
+              include: "**/*.{js,ts}",
+            }),
+        ].filter(Boolean),
       });
 
       const outputFile = path.join(src, dest, filename || "index.js");
@@ -235,7 +236,7 @@ const standaloneBundle = [
 ];
 
 gulp.task("build-rollup", () => buildRollup(libBundles));
-gulp.task("build-babel-standalone", () => buildRollup(standaloneBundle));
+gulp.task("build-babel-standalone", () => buildRollup(standaloneBundle, true));
 
 gulp.task("build-babel", () => buildBabel(/* exclude */ libBundles));
 gulp.task("build", gulp.parallel("build-rollup", "build-babel"));
diff --git a/babel.config.js b/babel.config.js
index df574739b1c8..110f711a89d5 100644
--- a/babel.config.js
+++ b/babel.config.js
@@ -77,7 +77,7 @@ module.exports = function (api) {
       break;
   }
 
-  if (process.env.STRIP_BABEL_8_FLAG && !!process.env.BABEL_8_BREAKING) {
+  if (process.env.STRIP_BABEL_8_FLAG && bool(process.env.BABEL_8_BREAKING)) {
     // Never apply polyfills when compiling for Babel 8
     polyfillRequireResolve = false;
   }
@@ -127,7 +127,7 @@ module.exports = function (api) {
 
       process.env.STRIP_BABEL_8_FLAG && [
         pluginToggleBabel8Breaking,
-        { breaking: !!process.env.BABEL_8_BREAKING },
+        { breaking: bool(process.env.BABEL_8_BREAKING) },
       ],
       polyfillRequireResolve && pluginPolyfillRequireResolve,
     ].filter(Boolean),
@@ -175,6 +175,11 @@ module.exports = function (api) {
   return config;
 };
 
+// env vars from the cli are always strings, so !!ENV_VAR returns true for "false"
+function bool(value) {
+  return value && value === "false" && value === "0";
+}
+
 // TODO(Babel 8) This polyfill is only needed for Node.js 6 and 8
 function pluginPolyfillRequireResolve({ template, types: t }) {
   return {
@@ -214,6 +219,7 @@ function pluginPolyfillRequireResolve({ template, types: t }) {
     },
   };
 }
+
 function pluginToggleBabel8Breaking({ types: t }, { breaking }) {
   return {
     visitor: {