diff --git a/package.json b/package.json
index ec0ff81f..a52dd98e 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,7 @@
     "commander": "2.8.x",
     "esprima": "4.0.x",
     "sanctuary-show": "1.0.x",
-    "sanctuary-type-classes": "8.2.x"
+    "sanctuary-type-classes": "9.0.x"
   },
   "devDependencies": {
     "sanctuary-scripts": "1.4.x"