diff --git a/src/anyio/_backends/_selector_thread.py b/src/anyio/_backends/_selector_thread.py
index 1aff007e..1d1bbafc 100644
--- a/src/anyio/_backends/_selector_thread.py
+++ b/src/anyio/_backends/_selector_thread.py
@@ -12,12 +12,10 @@
 import select
 import socket
 import threading
-import typing
 from typing import (
     TYPE_CHECKING,
     Any,
     Callable,
-    Union,
 )
 from weakref import WeakKeyDictionary