diff --git a/include/zephyr/kernel/internal/smp.h b/include/zephyr/kernel/internal/smp.h
index c5d40ddf9f8..58576201329 100644
--- a/include/zephyr/kernel/internal/smp.h
+++ b/include/zephyr/kernel/internal/smp.h
@@ -6,16 +6,6 @@
 #ifndef ZEPHYR_INCLUDE_KERNEL_INTERNAL_SMP_H_
 #define ZEPHYR_INCLUDE_KERNEL_INTERNAL_SMP_H_
 
-struct k_thread;
-
-/**
- * @internal
- */
-#ifdef CONFIG_SOF
-void z_smp_thread_init(void *arg, struct k_thread *thread);
-void z_smp_thread_swap(void);
-#endif
-
 void z_init_cpu(int id);
 void z_sched_ipi(void);
 
diff --git a/kernel/smp.c b/kernel/smp.c
index ff231710e53..45ec956dff9 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -106,19 +106,6 @@ static void wait_for_start_signal(atomic_t *start_flag)
 	}
 }
 
-/* Legacy interfaces for early-version SOF CPU bringup.  To be removed */
-#ifdef CONFIG_SOF
-void z_smp_thread_init(void *arg, struct k_thread *thread)
-{
-	z_dummy_thread_init(thread);
-	wait_for_start_signal(arg);
-}
-void z_smp_thread_swap(void)
-{
-	z_swap_unlocked();
-}
-#endif
-
 static inline void smp_init_top(void *arg)
 {
 	struct k_thread dummy_thread;