diff --git a/rest_framework-stubs/relations.pyi b/rest_framework-stubs/relations.pyi
index 6a223f96b..bf95a176f 100644
--- a/rest_framework-stubs/relations.pyi
+++ b/rest_framework-stubs/relations.pyi
@@ -135,7 +135,7 @@ class HyperlinkedRelatedField(RelatedField[_MT, str, Hyperlink]):
 class HyperlinkedIdentityField(HyperlinkedRelatedField): ...
 
 class SlugRelatedField(RelatedField[_MT, str, str]):
-    slug_field: str | None
+    slug_field: str
     def __init__(
         self,
         slug_field: str,