diff --git a/package.json b/package.json
index 627f7cbcb..04db62463 100644
--- a/package.json
+++ b/package.json
@@ -71,7 +71,7 @@
     "bluebird": "^3.1.5",
     "brfs": "^1.4.3",
     "browserify": "^14.1.0",
-    "chai": "^3.5.0",
+    "chai": "^4.0.1",
     "coveralls": "^2.11.4",
     "del-cli": "^0.2.1",
     "dot": "^1.0.3",