diff --git a/packages/emotion/package.json b/packages/emotion/package.json
index 965787bea..02b1cd1d6 100644
--- a/packages/emotion/package.json
+++ b/packages/emotion/package.json
@@ -17,7 +17,7 @@
     "clean": "rimraf dist",
     "rollup": "rollup -c ../../rollup.config.js",
     "watch": "rollup -c ../../rollup.config.js --watch",
-    "rollup:umd": "UMD=true rollup -c ../../rollup.config.js"
+    "rollup:umd": "cross-env UMD=true rollup -c ../../rollup.config.js"
   },
   "dependencies": {
     "babel-plugin-emotion": "^8.0.2-6",
@@ -25,6 +25,7 @@
   },
   "devDependencies": {
     "babel-cli": "^6.24.1",
+    "cross-env": "^5.0.5",
     "npm-run-all": "^4.0.2",
     "rimraf": "^2.6.1",
     "rollup": "^0.43.0"
diff --git a/packages/react-emotion/package.json b/packages/react-emotion/package.json
index c53d253c0..0bdd3ad38 100644
--- a/packages/react-emotion/package.json
+++ b/packages/react-emotion/package.json
@@ -14,7 +14,7 @@
     "clean": "rimraf dist",
     "rollup": "rollup -c ../../rollup.config.js",
     "watch": "rollup -c ../../rollup.config.js --watch",
-    "rollup:umd": "UMD=true rollup -c ../../rollup.config.js"
+    "rollup:umd": "cross-env UMD=true rollup -c ../../rollup.config.js"
   },
   "dependencies": {
     "babel-plugin-emotion": "^8.0.2-6",
@@ -24,6 +24,7 @@
     "emotion": "^8.0.2-6"
   },
   "devDependencies": {
+    "cross-env": "^5.0.5",
     "emotion": "^8.0.2-6",
     "npm-run-all": "^4.0.2",
     "rimraf": "^2.6.1",