diff --git a/composer.json b/composer.json
index d2d2e2b..1ec5e1f 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,7 @@
         "silverstripe/cms": "^4.0"
     },
     "require-dev": {
-        "phpunit/PHPUnit": "^5.7",
+        "phpunit/phpunit": "^5.7",
         "squizlabs/php_codesniffer": "^3.0"
     },
     "suggest": {