diff --git a/package.json b/package.json
index 16470b3..e573c38 100644
--- a/package.json
+++ b/package.json
@@ -50,7 +50,7 @@
   "devDependencies": {
     "aegir": "^11.0.0",
     "benchmark": "^2.1.3",
-    "chai": "^3.5.0",
+    "chai": "^4.0.1",
     "dirty-chai": "^1.2.2",
     "pre-commit": "^1.2.2"
   },