diff --git a/package.json b/package.json
index 63646fc..5d9b152 100644
--- a/package.json
+++ b/package.json
@@ -31,7 +31,7 @@
     "postcss": "^5.0.12"
   },
   "devDependencies": {
-    "chai": "^3.0.0",
+    "chai": "^4.0.0",
     "eslint": "2.13.1",
     "eslint-config-airbnb": "9.0.1",
     "eslint-plugin-import": "1.9.2",