diff --git a/src/click/testing.py b/src/click/testing.py
index 1eb81d29ed..7d0100bc06 100644
--- a/src/click/testing.py
+++ b/src/click/testing.py
@@ -22,7 +22,11 @@
 
     from .core import Command
 
-CaptureMode = t.Literal["sys", "fd"]
+
+if sys.platform == "win32":
+    CaptureMode: t.TypeAlias = t.Literal["sys"]  # pyright: ignore[reportRedeclaration]
+else:
+    CaptureMode: t.TypeAlias = t.Literal["sys", "fd"]  # pyright: ignore[reportRedeclaration]
 
 
 class EchoingStdin: