diff --git a/tests/extra/tsan.supp b/tests/extra/tsan.supp
index e7becb1a8b..982fcf728c 100644
--- a/tests/extra/tsan.supp
+++ b/tests/extra/tsan.supp
@@ -18,6 +18,8 @@ race:valent_sms_store_thread
 # src/plugins/sms/valent-sms-window.c
 race:_dl_deallocate_tls
 
+# tests/fixtures/valent-mock-channel.c
+race:valent_mock_channel_class_init
 
 #
 # Uninstrumented libraries (Yes, all of these are really necessary)