diff --git a/cpu/efm32/families/efm32gg12b/system.c b/cpu/efm32/families/efm32gg12b/system.c
index 0bc302fe67..908c8ab7d0 100644
--- a/cpu/efm32/families/efm32gg12b/system.c
+++ b/cpu/efm32/families/efm32gg12b/system.c
@@ -29,6 +29,7 @@
  ******************************************************************************/
 
 #include <stdint.h>
+#include "periph_conf.h"
 #include "em_device.h"
 
 /*******************************************************************************