diff --git a/package.json b/package.json
index 4f7fe4e..5fecce4 100644
--- a/package.json
+++ b/package.json
@@ -65,7 +65,7 @@
     "babel-eslint": "^7.1.1",
     "babel-plugin-transform-function-bind": "^6.5.2",
     "babel-preset-es2015": "^6.18.0",
-    "chai": "^3.5.0",
+    "chai": "^4.0.1",
     "coveralls": "^2.11.13",
     "dirty-chai": "^1.2.2",
     "eslint": "^3.10.2",