diff --git a/src/flask/helpers.py b/src/flask/helpers.py
index 90a0e0c6..44aa81c9 100644
--- a/src/flask/helpers.py
+++ b/src/flask/helpers.py
@@ -398,7 +398,7 @@ def _prepare_send_file_kwargs(**kwargs: t.Any) -> dict[str, t.Any]:
 
 
 def send_file(
-    path_or_file: os.PathLike[t.AnyStr] | str | t.BinaryIO,
+    path_or_file: os.PathLike[t.AnyStr] | str | t.BinaryIO | t.IO[bytes],
     mimetype: str | None = None,
     as_attachment: bool = False,
     download_name: str | None = None,