diff --git a/package.json b/package.json
index 939d01c..f3905b2 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
   },
   "devDependencies": {
     "mocha": "~3.1.2",
-    "chai": "~3.4.1",
+    "chai": "~4.0.1",
     "jshint": "~2.9.1-rc1"
   },
   "scripts": {