diff --git a/trio/_core/_tests/test_thread_cache.py b/trio/_core/_tests/test_thread_cache.py
index 5f19a5ac64..3cf750ca4b 100644
--- a/trio/_core/_tests/test_thread_cache.py
+++ b/trio/_core/_tests/test_thread_cache.py
@@ -5,7 +5,7 @@
 import sys
 from contextlib import contextmanager
 
-from .tutil import slow, gc_collect_harder, disable_threading_excepthook
+from .tutil import slow, gc_collect_harder
 from .. import _thread_cache
 from .._thread_cache import start_thread_soon, ThreadCache
 
diff --git a/trio/_core/_tests/tutil.py b/trio/_core/_tests/tutil.py
index e66127d20a..31bc59e4cb 100644
--- a/trio/_core/_tests/tutil.py
+++ b/trio/_core/_tests/tutil.py
@@ -95,19 +95,6 @@ def restore_unraisablehook():
         sys.unraisablehook = prev
 
 
-@contextmanager
-def disable_threading_excepthook():  # pragma: no cover # not used
-    if sys.version_info >= (3, 10):
-        threading.excepthook, prev = threading.__excepthook__, threading.excepthook
-    else:
-        threading.excepthook, prev = _noop, threading.excepthook
-
-    try:
-        yield
-    finally:
-        threading.excepthook = prev
-
-
 # template is like:
 #   [1, {2.1, 2.2}, 3] -> matches [1, 2.1, 2.2, 3] or [1, 2.2, 2.1, 3]
 def check_sequence_matches(seq, template):