diff --git a/sched/Makefile b/sched/Makefile
index 67da182ab6..26c790c84e 100644
--- a/sched/Makefile
+++ b/sched/Makefile
@@ -119,7 +119,9 @@ ENV_SRCS += env_clearenv.c env_getenv.c env_putenv.c env_setenv.c env_unsetenv.c
 WDOG_SRCS = wd_initialize.c wd_create.c wd_start.c wd_cancel.c wd_delete.c
 WDOG_SRCS += wd_gettime.c
 
-TIME_SRCS = sched_processtimer.c
+ifneq ($(CONFIG_SCHED_TICKLESS),y)
+TIME_SRCS += sched_processtimer.c
+endif
 
 ifneq ($(CONFIG_DISABLE_SIGNALS),y)
 TIME_SRCS += nanosleep.c