diff --git a/tests/Makefile b/tests/Makefile
index 7ab4d9c..796d5fc 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -177,6 +177,7 @@
 
 clean:
 ifndef WINDOWS
+	$(MAKE) -C psa-client-server/psasim clean
 	rm -rf $(BINARIES) *.c *.datax
 	rm -f src/*.o src/drivers/*.o src/test_helpers/*.o src/libmbed* src/test_keys.h src/test_certs.h
 	rm -f src/test_keys.h src/test_certs.h