diff --git a/third_party/silabs/Makefile.am b/third_party/silabs/Makefile.am
index 68fefc73a..187b465bb 100644
--- a/third_party/silabs/Makefile.am
+++ b/third_party/silabs/Makefile.am
@@ -58,6 +58,10 @@ override CXXFLAGS  := $(filter-out -pedantic-errors,$(CXXFLAGS))
 override CFLAGS    := $(filter-out -Wshadow,$(CFLAGS))
 override CXXFLAGS  := $(filter-out -Wshadow,$(CXXFLAGS))
 
+# Do not enable -Wundef for Silicon Labs SDK sources
+override CFLAGS    := $(filter-out -Wundef,$(CFLAGS))
+override CXXFLAGS  := $(filter-out -Wundef,$(CXXFLAGS))
+
 EFR32_BOARD_DIR = $(shell echo $(BOARD) | tr A-Z a-z)
 
 SDK_SRC_DIR = $(top_srcdir)/third_party/silabs/gecko_sdk_suite/v2.7