diff --git a/narwhals/typing.py b/narwhals/typing.py
index 4923bbed7b..3ad49f1d0e 100644
--- a/narwhals/typing.py
+++ b/narwhals/typing.py
@@ -44,6 +44,8 @@ def __dataframe__(self, *args: Any, **kwargs: Any) -> Any: ...
 
 
 class CompliantSeries(Protocol):
+    @property
+    def dtype(self) -> DType: ...
     @property
     def name(self) -> str: ...
     def __narwhals_series__(self) -> CompliantSeries: ...