diff --git a/package.json b/package.json
index 84d60341..a8cd8d34 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
   },
   "homepage": "http://lostgrid.org",
   "devDependencies": {
-    "chai": "^3.5",
+    "chai": "^4.1.2",
     "clean-css": "^4.1.6",
     "codecov": "^2.1.0",
     "eslint": "^3.16",