diff --git a/package.json b/package.json
index 4a5cfd1..d0f6426 100644
--- a/package.json
+++ b/package.json
@@ -56,7 +56,7 @@
     "babel-core": "^6.18.0",
     "babel-preset-es2015-node4": "^2.1.0",
     "babel-register": "^6.18.0",
-    "chai": "^3.2.0",
+    "chai": "^4.0.0",
     "coveralls": "^2.11.14",
     "eslint": "^3.8.1",
     "eslint-plugin-import": "^2.0.1",