diff --git a/src/System.php b/src/System.php
index e6517f3..47d3729 100644
--- a/src/System.php
+++ b/src/System.php
@@ -49,7 +49,7 @@ public function registerOs(array $classNames)
             $os = new $className;
 
             if (!$os instanceof OsInterface) {
-                throw new \UnexpectedValueException("Class {$className} must implement ".OsIntefrace::class);
+                throw new \UnexpectedValueException("Class {$className} must implement ".OsInterface::class);
             }
 
             if ($os->inUse()) {