diff --git a/packages/react-is/package.json b/packages/react-is/package.json
index 403e7a7fefd4e..49359a06f01e0 100644
--- a/packages/react-is/package.json
+++ b/packages/react-is/package.json
@@ -3,6 +3,7 @@
   "version": "18.2.0",
   "description": "Brand checking of React Elements.",
   "main": "index.js",
+  "sideEffects": false,
   "repository": {
     "type": "git",
     "url": "https://github.com/facebook/react.git",