diff --git a/package.json b/package.json
index 9110bad..290b6a7 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
   },
   "repository": "dashed/shallowequal",
   "license": "MIT",
+  "sideEffects": false,
   "files": [
     "index.js",
     "index.js.flow",
@@ -65,4 +66,4 @@
     "lint-staged": "10.0.9",
     "prettier": "1.19.1"
   }
-}
+}
\ No newline at end of file