diff --git a/kernel/sched.c b/kernel/sched.c
index 7cc4c6451be..756a38fb7a7 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -361,6 +361,12 @@ void k_sched_time_slice_set(int32_t slice, int prio)
 	LOCKED(&sched_spinlock) {
 		_current_cpu->slice_ticks = 0;
 		slice_time = k_ms_to_ticks_ceil32(slice);
+		if (IS_ENABLED(CONFIG_TICKLESS_KERNEL) && slice > 0) {
+			/* It's not possible to reliably set a 1-tick
+			 * timeout if ticks aren't regular.
+			 */
+			slice_time = MAX(2, slice_time);
+		}
 		slice_max_prio = prio;
 		z_reset_time_slice();
 	}
diff --git a/tests/kernel/mem_protect/syscalls/prj.conf b/tests/kernel/mem_protect/syscalls/prj.conf
index c579ae5c989..0b123068b3d 100644
--- a/tests/kernel/mem_protect/syscalls/prj.conf
+++ b/tests/kernel/mem_protect/syscalls/prj.conf
@@ -1,5 +1,5 @@
 CONFIG_ZTEST=y
 CONFIG_TEST_USERSPACE=y
 CONFIG_TIMESLICING=y
-CONFIG_TIMESLICE_SIZE=10
+CONFIG_TIMESLICE_SIZE=20
 CONFIG_APPLICATION_DEFINED_SYSCALL=y
diff --git a/tests/kernel/workq/critical/src/main.c b/tests/kernel/workq/critical/src/main.c
index 44fa9107b0f..b3739fb7d40 100644
--- a/tests/kernel/workq/critical/src/main.c
+++ b/tests/kernel/workq/critical/src/main.c
@@ -166,7 +166,7 @@ void regression_thread(void *arg1, void *arg2, void *arg3)
 		      "Unexpected value for <critical_var>");
 
 	TC_PRINT("Enable timeslicing at %u\n", k_uptime_get_32());
-	k_sched_time_slice_set(10, 10);
+	k_sched_time_slice_set(20, 10);
 
 	k_sem_give(&ALT_SEM);   /* Re-activate alternate_thread() */