diff --git a/src/textual/_types.py b/src/textual/_types.py
index 5dc7aa107a..14f6b90b4e 100644
--- a/src/textual/_types.py
+++ b/src/textual/_types.py
@@ -1,5 +1,5 @@
 import sys
-from typing import Awaitable, Callable, Optional, TYPE_CHECKING
+from typing import Awaitable, Callable, List, Optional, TYPE_CHECKING
 from rich.segment import Segment
 
 if sys.version_info >= (3, 8):
@@ -28,4 +28,4 @@ async def post_message(self, message: "Message") -> bool:
 
 MessageHandler = Callable[["Message"], Awaitable]
 
-Lines = list[list[Segment]]
\ No newline at end of file
+Lines = List[List[Segment]]