diff --git a/package.json b/package.json
index db73aba..f86bbfe 100644
--- a/package.json
+++ b/package.json
@@ -50,7 +50,7 @@
     "babel-preset-env": "^1.6.0",
     "babel-preset-stage-0": "^6.5.0",
     "babel-register": "^6.14.0",
-    "chai": "^3.5.0",
+    "chai": "^4.2.0",
     "eslint": "^3.13.1",
     "eslint-config-trigen": "^1.0.0",
     "mocha": "^3.0.2"