diff --git a/packages/metro-babel-transformer/src/index.js b/packages/metro-babel-transformer/src/index.js
index 58dfa4f73b..fb01801fdf 100644
--- a/packages/metro-babel-transformer/src/index.js
+++ b/packages/metro-babel-transformer/src/index.js
@@ -44,7 +44,9 @@ export type BabelTransformer = {|
 
 function transform({filename, options, plugins, src}: BabelTransformerArgs) {
   const OLD_BABEL_ENV = process.env.BABEL_ENV;
-  process.env.BABEL_ENV = options.dev ? 'development' : 'production';
+  process.env.BABEL_ENV = options.dev
+    ? 'development'
+    : process.env.BABEL_ENV || 'production';
 
   try {
     const {ast} = transformSync(src, {
diff --git a/packages/metro-react-native-babel-transformer/src/index.js b/packages/metro-react-native-babel-transformer/src/index.js
index d60564f754..d5df2c8c69 100644
--- a/packages/metro-react-native-babel-transformer/src/index.js
+++ b/packages/metro-react-native-babel-transformer/src/index.js
@@ -141,7 +141,9 @@ function buildBabelConfig(filename, options, plugins?: BabelPlugins = []) {
 
 function transform({filename, options, src, plugins}: BabelTransformerArgs) {
   const OLD_BABEL_ENV = process.env.BABEL_ENV;
-  process.env.BABEL_ENV = options.dev ? 'development' : 'production';
+  process.env.BABEL_ENV = options.dev
+    ? 'development'
+    : process.env.BABEL_ENV || 'production';
 
   try {
     const babelConfig = buildBabelConfig(filename, options, plugins);