diff --git a/cpu/cc2538/Makefile.dep b/cpu/cc2538/Makefile.dep
index 4f899edb6d..b9e01ef586 100644
--- a/cpu/cc2538/Makefile.dep
+++ b/cpu/cc2538/Makefile.dep
@@ -3,4 +3,8 @@ ifneq (,$(filter cc2538_rf,$(USEMODULE)))
   USEMODULE += netif
 endif
 
+ifneq (,$(filter periph_rtc,$(USEMODULE)))
+  USEMODULE += rtt_rtc
+endif
+
 USEMODULE += pm_layered