diff --git a/Directory.mk b/Directory.mk
index fae7cb9d1..6ce0149ec 100644
--- a/Directory.mk
+++ b/Directory.mk
@@ -42,6 +42,7 @@ CONFIGSUBDIRS := $(filter-out $(dir $(wildcard *$(DELIM)Kconfig)),$(SUBDIRS))
 CLEANSUBDIRS  := $(dir $(wildcard *$(DELIM).built))
 CLEANSUBDIRS  += $(dir $(wildcard *$(DELIM).depend))
 CLEANSUBDIRS  += $(dir $(wildcard *$(DELIM).kconfig))
+CLEANSUBDIRS  := $(sort $(CLEANSUBDIRS))
 
 all: nothing