diff --git a/package.json b/package.json
index cbd3fab..2046d68 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
   "devDependencies": {
     "babel-core": "^6.0.12",
     "babel-preset-es2015": "^6.0.12",
-    "chai": "^3.0.0",
+    "chai": "^4.0.0",
     "coveralls": "^2.11.2",
     "cz-conventional-changelog": "^1.1.5",
     "del": "^2.0.0",