diff --git a/package.json b/package.json
index 3c64bc2..4f119eb 100644
--- a/package.json
+++ b/package.json
@@ -47,7 +47,7 @@
   },
   "dependencies": {
     "async": "^2.0.1",
-    "chai": "~3.5.0",
+    "chai": "~4.0.1",
     "coffee-errors": "^0.8.6",
     "coffee-script": "~1.12.1",
     "csonschema": "^0.5.1",