diff --git a/composer.json b/composer.json
index 0cb9e28..7872481 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,7 @@
     },
     "require-dev": {
         "mockery/mockery": "1.0.0",
-        "phpunit/PHPUnit": "5.7.25",
+        "phpunit/phpunit": "5.7.25",
         "squizlabs/php_codesniffer": "3.1.1"
     },
     "suggest": {