diff --git a/makefiles/docker.inc.mk b/makefiles/docker.inc.mk
index e24f0368e0..cfa6cc7c4e 100644
--- a/makefiles/docker.inc.mk
+++ b/makefiles/docker.inc.mk
@@ -66,6 +66,7 @@ export DOCKER_ENV_VARS += \
   SCANBUILD_OUTPUTDIR \
   SIZE \
   TOOLCHAIN \
+  TEST_KCONFIG \
   UNDEF \
   #