diff --git a/src/Overseer.php b/src/Overseer.php
index 672f475..8fcb90c 100644
--- a/src/Overseer.php
+++ b/src/Overseer.php
@@ -108,7 +108,7 @@ public function saveAssignment(Assignment $assignment)
      * @param string $subjectId
      * @param string $subjectName
      *
-     * @return Assignment
+     * @return Assignment|null
      */
     public function getAssignment($subjectId, $subjectName)
     {
diff --git a/src/Storage/AssignmentStorage.php b/src/Storage/AssignmentStorage.php
index 6be60d6..f8dfbce 100644
--- a/src/Storage/AssignmentStorage.php
+++ b/src/Storage/AssignmentStorage.php
@@ -22,7 +22,7 @@ public function deleteAssignment(Assignment $assignment);
      * @param mixed  $subjectId
      * @param string $subjectName
      *
-     * @return Assignment
+     * @return Assignment|null
      */
     public function getAssignment($subjectId, $subjectName);