diff --git a/include/kernel.h b/include/kernel.h
index eea4e62..9c353d0 100644
--- a/include/kernel.h
+++ b/include/kernel.h
@@ -2024,9 +2024,9 @@
  *
  * @return The user data.
  */
-__syscall void *k_timer_user_data_get(struct k_timer *timer);
+__syscall void *k_timer_user_data_get(const struct k_timer *timer);
 
-static inline void *z_impl_k_timer_user_data_get(struct k_timer *timer)
+static inline void *z_impl_k_timer_user_data_get(const struct k_timer *timer)
 {
 	return timer->user_data;
 }
diff --git a/kernel/timer.c b/kernel/timer.c
index cc1c918..d338c17 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -256,7 +256,7 @@
 }
 #include <syscalls/k_timer_expires_ticks_mrsh.c>
 
-static inline void *z_vrfy_k_timer_user_data_get(struct k_timer *timer)
+static inline void *z_vrfy_k_timer_user_data_get(const struct k_timer *timer)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(timer, K_OBJ_TIMER));
 	return z_impl_k_timer_user_data_get(timer);