diff --git a/composer.json b/composer.json
index 2f59d0fe..dd31dce5 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
         "php": ">=5.2"
     },
     "autoload": {
-        "psr-0": { "HTMLPurifier": "library/" },
+        "psr-0": { "HTMLPurifier_": "library/" },
         "files": ["library/HTMLPurifier.composer.php"]
     }
 }