diff --git a/test_runner/regress/test_tenant_detach.py b/test_runner/regress/test_tenant_detach.py
index ef6ac1527e..1beca58298 100644
--- a/test_runner/regress/test_tenant_detach.py
+++ b/test_runner/regress/test_tenant_detach.py
@@ -272,8 +272,10 @@ def test_tenant_detach_smoke(neon_env_builder: NeonEnvBuilder):
         bogus_timeline_id = TimelineId.generate()
         pageserver_http.timeline_gc(tenant_id, bogus_timeline_id, 0)
 
-        # the error will be printed to the log too
+    # the error will be printed to the log too
     env.pageserver.allowed_errors.append(".*gc target timeline does not exist.*")
+    # Timelines get stopped during detach, ignore the gc calls that error, whitnessing that
+    env.pageserver.allowed_errors.append(".*InternalServerError\\(timeline is Stopping.*")
 
     # Detach while running manual GC.
     # It should wait for manual GC to finish because it runs in a task associated with the tenant.