diff --git a/package.json b/package.json
index 6809a85..7bb3ce8 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
   "dependencies": {},
   "devDependencies": {
     "mocha": "~1.8",
-    "chai": "~1.5",
+    "chai": "~4.0.0",
     "grunt-npm": "~0.0.2",
     "grunt": "~0.4.1",
     "grunt-bump": "~0.0.11",