diff --git a/package.json b/package.json
index 43a0ed5..bfdf434 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,7 @@
   ],
   "dependencies": {
     "@the-grid/schema": "^0.1.1",
-    "chai": "~3.5.0",
+    "chai": "~4.0.0",
     "coffee-script": "~1.12.0",
     "debug": "~2.6.0",
     "graphlib": "~2.1.0",