diff --git a/drivers/timer/npcx_itim_timer.c b/drivers/timer/npcx_itim_timer.c
index a54db566d9..fba2bc2b3c 100644
--- a/drivers/timer/npcx_itim_timer.c
+++ b/drivers/timer/npcx_itim_timer.c
@@ -58,6 +58,7 @@ LOG_MODULE_REGISTER(itim, LOG_LEVEL_ERR);
 #define NPCX_ITIM_CLK_SEL_DELAY 92 /* Delay for clock selection (Unit:us) */
 /* Timeout for enabling ITIM module: 100us (Unit:cycles) */
 #define NPCX_ITIM_EN_TIMEOUT_CYCLES (100 * SYS_CYCLES_PER_USEC)
+#define SYS_CYC_PER_EVT_CYC         (sys_clock_hw_cycles_per_sec() / EVT_CYCLES_PER_SEC)
 
 /* Instance of system and event timers */
 static struct itim64_reg *const sys_tmr = (struct itim64_reg *)
@@ -70,6 +71,9 @@ static const struct npcx_clk_cfg itim_clk_cfg[] = NPCX_DT_CLK_CFG_ITEMS_LIST(0);
 static struct k_spinlock lock;
 /* Announced cycles in system timer before executing sys_clock_announce() */
 static uint64_t cyc_sys_announced;
+static uint64_t last_ticks;
+static uint32_t last_elapsed;
+
 /* Current target cycles of time-out signal in event timer */
 static uint32_t cyc_evt_timeout;
 /* Total cycles of system timer stopped in "sleep/deep sleep" mode */
@@ -136,18 +140,33 @@ static inline void npcx_itim_evt_disable(void)
 /* ITIM local functions */
 static int npcx_itim_start_evt_tmr_by_tick(int32_t ticks)
 {
+	k_spinlock_key_t key = k_spin_lock(&lock);
+
 	/*
 	 * Get desired cycles of event timer from the requested ticks which
 	 * round up to next tick boundary.
 	 */
+
 	if (ticks == K_TICKS_FOREVER) {
 		cyc_evt_timeout = NPCX_ITIM32_MAX_CNT;
 	} else {
+		uint64_t next_cycs;
+		uint64_t curr = npcx_itim_get_sys_cyc64();
+		uint32_t dcycles;
+
 		if (ticks <= 0) {
 			ticks = 1;
 		}
-		cyc_evt_timeout = MIN(EVT_CYCLES_FROM_TICKS(ticks),
-				      NPCX_ITIM32_MAX_CNT);
+
+		next_cycs = (last_ticks + last_elapsed + ticks) * SYS_CYCLES_PER_TICK;
+		if (unlikely(next_cycs <= curr)) {
+			cyc_evt_timeout = 1;
+		} else {
+			dcycles = next_cycs - curr;
+			cyc_evt_timeout =
+				CLAMP((dcycles / SYS_CYC_PER_EVT_CYC), 1, NPCX_ITIM32_MAX_CNT);
+		}
+
 	}
 	LOG_DBG("ticks %x, cyc_evt_timeout %x", ticks, cyc_evt_timeout);
 
@@ -159,9 +178,9 @@ static int npcx_itim_start_evt_tmr_by_tick(int32_t ticks)
 	/* Upload counter of event timer */
 	evt_tmr->ITCNT32 = MAX(cyc_evt_timeout - 1, 1);
 
+	k_spin_unlock(&lock, key);
 	/* Enable event timer and start ticking */
 	return npcx_itim_evt_enable();
-
 }
 
 static void npcx_itim_evt_isr(const struct device *dev)
@@ -175,11 +194,12 @@ static void npcx_itim_evt_isr(const struct device *dev)
 
 	if (IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
 		k_spinlock_key_t key = k_spin_lock(&lock);
-		uint32_t delta_ticks = (uint32_t)((npcx_itim_get_sys_cyc64() -
-				cyc_sys_announced) / SYS_CYCLES_PER_TICK);
+		uint64_t curr = npcx_itim_get_sys_cyc64();
+		uint32_t delta_ticks = (uint32_t)((curr - cyc_sys_announced) / SYS_CYCLES_PER_TICK);
 
-		/* Store announced cycles of system timer */
-		cyc_sys_announced = npcx_itim_get_sys_cyc64();
+		cyc_sys_announced += delta_ticks * SYS_CYCLES_PER_TICK;
+		last_ticks += delta_ticks;
+		last_elapsed = 0;
 		k_spin_unlock(&lock, key);
 
 		/* Informs kernel that specified number of ticks have elapsed */
@@ -252,11 +272,13 @@ uint32_t sys_clock_elapsed(void)
 
 	k_spinlock_key_t key = k_spin_lock(&lock);
 	uint64_t delta_cycle = npcx_itim_get_sys_cyc64() - cyc_sys_announced;
+	uint32_t delta_ticks = (uint32_t)delta_cycle / SYS_CYCLES_PER_TICK;
 
+	last_elapsed = delta_ticks;
 	k_spin_unlock(&lock, key);
 
 	/* Return how many ticks elapsed since last sys_clock_announce() call */
-	return (uint32_t)(delta_cycle / SYS_CYCLES_PER_TICK);
+	return delta_ticks;
 }
 
 uint32_t sys_clock_cycle_get_32(void)