diff --git a/package.json b/package.json
index 7705035..2b2a3bf 100644
--- a/package.json
+++ b/package.json
@@ -65,7 +65,7 @@
     "babel-preset-react": "^6.11.1",
     "babel-preset-stage-1": "^6.13.0",
     "babel-register": "^6.14.0",
-    "chai": "^3.5.0",
+    "chai": "^4.0.0",
     "coveralls": "^2.11.15",
     "crater-util": "^1.2.2",
     "cross-spawn": "^5.0.1",