diff --git a/composer.json b/composer.json
index a2255b5f6..603756f00 100644
--- a/composer.json
+++ b/composer.json
@@ -32,7 +32,7 @@
     "vlucas/phpdotenv": "^2.4"
   },
   "require-dev": {
-    "phpunit/PHPUnit": "^5.7",
+    "phpunit/phpunit": "^5.7",
     "silverstripe/versioned": "^1.0@dev",
     "silverstripe/behat-extension": "^2.1.0",
     "silverstripe/serve": "dev-master",