diff --git a/arch/arm/src/cxd56xx/cxd56_rtc_lowerhalf.c b/arch/arm/src/cxd56xx/cxd56_rtc_lowerhalf.c
index ad9fda6a22c..cf37e35c37d 100644
--- a/arch/arm/src/cxd56xx/cxd56_rtc_lowerhalf.c
+++ b/arch/arm/src/cxd56xx/cxd56_rtc_lowerhalf.c
@@ -269,7 +269,7 @@ static int cxd56_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -324,7 +324,7 @@ static int cxd56_setalarm(FAR struct rtc_lowerhalf_s *lower,
 
       /* Convert the RTC time to a timespec (1 second accuracy) */
 
-      lowerinfo.as_time.tv_sec  = mktime((FAR struct tm *)&alarminfo->time);
+      lowerinfo.as_time.tv_sec  = timegm((FAR struct tm *)&alarminfo->time);
       lowerinfo.as_time.tv_nsec = 0;
 
       /* And set the alarm */
diff --git a/arch/arm/src/imxrt/imxrt_rtc_lowerhalf.c b/arch/arm/src/imxrt/imxrt_rtc_lowerhalf.c
index 5e2a66b9bb2..116c41eaa19 100644
--- a/arch/arm/src/imxrt/imxrt_rtc_lowerhalf.c
+++ b/arch/arm/src/imxrt/imxrt_rtc_lowerhalf.c
@@ -237,7 +237,7 @@ static int imxrt_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -311,7 +311,7 @@ static int imxrt_setalarm(FAR struct rtc_lowerhalf_s *lower,
 
       /* Convert the RTC time to a timespec (1 second accuracy) */
 
-      ts.tv_sec   = mktime((FAR struct tm *)&alarminfo->time);
+      ts.tv_sec   = timegm((FAR struct tm *)&alarminfo->time);
       ts.tv_nsec  = 0;
 
       /* Remember the callback information */
diff --git a/arch/arm/src/kinetis/kinetis_rtc_lowerhalf.c b/arch/arm/src/kinetis/kinetis_rtc_lowerhalf.c
index f332f84b12b..1111f091efd 100644
--- a/arch/arm/src/kinetis/kinetis_rtc_lowerhalf.c
+++ b/arch/arm/src/kinetis/kinetis_rtc_lowerhalf.c
@@ -273,7 +273,7 @@ static int kinetis_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Set the time (to one second accuracy) */
@@ -324,7 +324,7 @@ static int kinetis_setalarm(FAR struct rtc_lowerhalf_s *lower,
 
       /* Convert from Julian calendar time to epoch time */
 
-      tp.tv_sec = mktime((FAR struct tm *)&alarminfo->time) ;
+      tp.tv_sec = timegm((FAR struct tm *)&alarminfo->time) ;
 
       /* And set the alarm */
 
@@ -392,7 +392,7 @@ kinetis_setrelative(FAR struct rtc_lowerhalf_s *lower,
           return ret;
         }
 
-      ts.tv_sec  = mktime(&time);
+      ts.tv_sec  = timegm(&time);
       ts.tv_nsec = 0;
 #else
       /* Get the current time in broken out format */
diff --git a/arch/arm/src/lc823450/lc823450_rtc.c b/arch/arm/src/lc823450/lc823450_rtc.c
index 03a0c89f746..b5a4952b3b0 100644
--- a/arch/arm/src/lc823450/lc823450_rtc.c
+++ b/arch/arm/src/lc823450/lc823450_rtc.c
@@ -170,7 +170,7 @@ volatile bool g_rtc_enabled = false;
 static void tm_divider(struct tm *tm, int divn, int divm)
 {
   time_t tt;
-  tt = mktime(tm);
+  tt = timegm(tm);
   tt = (time_t) ((uint64_t)tt * divn / divm);
   gmtime_r(&tt, tm);
 }
@@ -690,7 +690,7 @@ int up_rtc_getrawtime(FAR struct timespec *ts)
 #endif /* CONFIG_RTC_DIV */
 
   ts->tv_nsec = 0;
-  ts->tv_sec = mktime(&tm);
+  ts->tv_sec = timegm(&tm);
   return 0;
 }
 
diff --git a/arch/arm/src/lpc54xx/lpc54_rtc_lowerhalf.c b/arch/arm/src/lpc54xx/lpc54_rtc_lowerhalf.c
index d5e69687171..7b106d812e6 100644
--- a/arch/arm/src/lpc54xx/lpc54_rtc_lowerhalf.c
+++ b/arch/arm/src/lpc54xx/lpc54_rtc_lowerhalf.c
@@ -252,7 +252,7 @@ static int lpc54_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -320,7 +320,7 @@ static int lpc54_setalarm(FAR struct rtc_lowerhalf_s *lower,
 
       /* Convert the RTC time to a timespec (1 second accuracy) */
 
-      ts.tv_sec   = mktime((FAR struct tm *)&alarminfo->time);
+      ts.tv_sec   = timegm((FAR struct tm *)&alarminfo->time);
       ts.tv_nsec  = 0;
 
       /* Remember the callback information */
diff --git a/arch/arm/src/max326xx/common/max326_rtc_lowerhalf.c b/arch/arm/src/max326xx/common/max326_rtc_lowerhalf.c
index ed81d37c6c0..06dc273498e 100644
--- a/arch/arm/src/max326xx/common/max326_rtc_lowerhalf.c
+++ b/arch/arm/src/max326xx/common/max326_rtc_lowerhalf.c
@@ -313,7 +313,7 @@ static int max326_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -382,7 +382,7 @@ static int max326_setalarm(FAR struct rtc_lowerhalf_s *lower,
 
       /* Convert the RTC time to a timespec (1 second accuracy) */
 
-      ts.tv_sec   = mktime((FAR struct tm *)&alarminfo->time);
+      ts.tv_sec   = timegm((FAR struct tm *)&alarminfo->time);
       ts.tv_nsec  = 0;
 
       /* Remember the callback information */
@@ -459,7 +459,7 @@ static int max326_setrelative(FAR struct rtc_lowerhalf_s *lower,
           return ret;
         }
 
-      ts.tv_sec  = mktime(&time);
+      ts.tv_sec  = timegm(&time);
       ts.tv_nsec = 0;
 
 #elif defined(CONFIG_RTC_HIRES)
diff --git a/arch/arm/src/sam34/sam_rtc.c b/arch/arm/src/sam34/sam_rtc.c
index cad96710b81..bba3bd5cfc1 100644
--- a/arch/arm/src/sam34/sam_rtc.c
+++ b/arch/arm/src/sam34/sam_rtc.c
@@ -803,7 +803,7 @@ int up_rtc_gettime(FAR struct timespec *tp)
                             RTC_CALR_YEAR_SHIFT)
              - 1900;
 
-  tp->tv_sec = mktime(&t);
+  tp->tv_sec = timegm(&t);
   tp->tv_nsec = (((rtt_val - g_rtt_offset) & (CONFIG_RTC_FREQUENCY - 1)) *
                    1000000000ull) / CONFIG_RTC_FREQUENCY;
 
diff --git a/arch/arm/src/stm32/stm32_rtc_lowerhalf.c b/arch/arm/src/stm32/stm32_rtc_lowerhalf.c
index 98d38d6f6cc..1d1e40ac0ab 100644
--- a/arch/arm/src/stm32/stm32_rtc_lowerhalf.c
+++ b/arch/arm/src/stm32/stm32_rtc_lowerhalf.c
@@ -346,7 +346,7 @@ static int stm32_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -469,7 +469,7 @@ static int stm32_setalarm(FAR struct rtc_lowerhalf_s *lower,
 
       /* Convert the RTC time to a timespec (1 second accuracy) */
 
-      ts.tv_sec   = mktime((FAR struct tm *)&alarminfo->time);
+      ts.tv_sec   = timegm((FAR struct tm *)&alarminfo->time);
       ts.tv_nsec  = 0;
 
       /* Remember the callback information */
@@ -541,7 +541,7 @@ static int stm32_setrelative(FAR struct rtc_lowerhalf_s *lower,
         {
           /* Convert to seconds since the epoch */
 
-          seconds = mktime(&time);
+          seconds = timegm(&time);
 
           /* Add the seconds offset.  Add one to the number of seconds
            * because we are unsure of the phase of the timer.
@@ -599,7 +599,7 @@ static int stm32_setrelative(FAR struct rtc_lowerhalf_s *lower,
           return ret;
         }
 
-      ts.tv_sec  = mktime(&time);
+      ts.tv_sec  = timegm(&time);
       ts.tv_nsec = 0;
 
 #elif defined(CONFIG_RTC_HIRES)
diff --git a/arch/arm/src/stm32f7/stm32_rtc_lowerhalf.c b/arch/arm/src/stm32f7/stm32_rtc_lowerhalf.c
index f244173a997..4edfc6ff4dd 100644
--- a/arch/arm/src/stm32f7/stm32_rtc_lowerhalf.c
+++ b/arch/arm/src/stm32f7/stm32_rtc_lowerhalf.c
@@ -311,7 +311,7 @@ static int stm32_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -458,7 +458,7 @@ static int stm32_setrelative(FAR struct rtc_lowerhalf_s *lower,
         {
           /* Convert to seconds since the epoch */
 
-          seconds = mktime(&time);
+          seconds = timegm(&time);
 
           /* Add the seconds offset.  Add one to the number of seconds
            * because we are unsure of the phase of the timer.
diff --git a/arch/arm/src/stm32h7/stm32_rtc_lowerhalf.c b/arch/arm/src/stm32h7/stm32_rtc_lowerhalf.c
index 528e11dbcd3..bc855cd10b6 100644
--- a/arch/arm/src/stm32h7/stm32_rtc_lowerhalf.c
+++ b/arch/arm/src/stm32h7/stm32_rtc_lowerhalf.c
@@ -312,7 +312,7 @@ static int stm32_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -459,7 +459,7 @@ static int stm32_setrelative(FAR struct rtc_lowerhalf_s *lower,
         {
           /* Convert to seconds since the epoch */
 
-          seconds = mktime(&time);
+          seconds = timegm(&time);
 
           /* Add the seconds offset.  Add one to the number of seconds
            * because we are unsure of the phase of the timer.
diff --git a/arch/arm/src/stm32l4/stm32l4_rtc_lowerhalf.c b/arch/arm/src/stm32l4/stm32l4_rtc_lowerhalf.c
index deb23c7acb9..e36bd0b16b8 100644
--- a/arch/arm/src/stm32l4/stm32l4_rtc_lowerhalf.c
+++ b/arch/arm/src/stm32l4/stm32l4_rtc_lowerhalf.c
@@ -441,7 +441,7 @@ stm32l4_setrelative(FAR struct rtc_lowerhalf_s *lower,
         {
           /* Convert to seconds since the epoch */
 
-          seconds = mktime(&time);
+          seconds = timegm(&time);
 
           /* Add the seconds offset.  Add one to the number of seconds
            * because we are unsure of the phase of the timer.
diff --git a/arch/renesas/src/rx65n/rx65n_rtc.c b/arch/renesas/src/rx65n/rx65n_rtc.c
index ad3f1d1b6d5..c1aefa9ba43 100644
--- a/arch/renesas/src/rx65n/rx65n_rtc.c
+++ b/arch/renesas/src/rx65n/rx65n_rtc.c
@@ -531,7 +531,7 @@ int up_rtc_gettime(FAR struct timespec *tp)
 
       t.tm_year = rtc_bcd2dec((uint8_t) (bcd_years & 0xff)) + 100;
 
-          tp->tv_sec = mktime(&t);
+          tp->tv_sec = timegm(&t);
           tp->tv_nsec = 0;
     }
 
diff --git a/arch/renesas/src/rx65n/rx65n_rtc_lowerhalf.c b/arch/renesas/src/rx65n/rx65n_rtc_lowerhalf.c
index 50481aa45ad..e545848608c 100644
--- a/arch/renesas/src/rx65n/rx65n_rtc_lowerhalf.c
+++ b/arch/renesas/src/rx65n/rx65n_rtc_lowerhalf.c
@@ -302,7 +302,7 @@ static int rx65n_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -445,7 +445,7 @@ static int rx65n_setrelative(FAR struct rtc_lowerhalf_s *lower,
           return ret;
         }
 
-      ts.tv_sec  = mktime(&time);
+      ts.tv_sec  = timegm(&time);
       ts.tv_nsec = 0;
 
 #elif defined(CONFIG_RTC_HIRES)
@@ -456,7 +456,7 @@ static int rx65n_setrelative(FAR struct rtc_lowerhalf_s *lower,
         {
           /* Convert to seconds since the epoch */
 
-          seconds = mktime(&time);
+          seconds = timegm(&time);
 
           /* Add the seconds offset.  Add one to the number of seconds
            * because we are unsure of the phase of the timer.
diff --git a/arch/sim/src/sim/up_rtc.c b/arch/sim/src/sim/up_rtc.c
index 628ae82b56a..d119253f6ef 100644
--- a/arch/sim/src/sim/up_rtc.c
+++ b/arch/sim/src/sim/up_rtc.c
@@ -83,7 +83,7 @@ static int sim_rtc_rdtime(FAR struct rtc_lowerhalf_s *lower,
 static int sim_rtc_settime(FAR struct rtc_lowerhalf_s *lower,
                            FAR const struct rtc_time *rtctime)
 {
-  g_sim_delta = mktime((FAR struct tm *)rtctime);
+  g_sim_delta = timegm((FAR struct tm *)rtctime);
   g_sim_delta *= NSEC_PER_SEC;
   g_sim_delta += rtctime->tm_nsec;
   g_sim_delta -= host_gettime(true);
diff --git a/arch/z80/src/ez80/ez80_rtc_lowerhalf.c b/arch/z80/src/ez80/ez80_rtc_lowerhalf.c
index a40cc236839..8b3bb874233 100644
--- a/arch/z80/src/ez80/ez80_rtc_lowerhalf.c
+++ b/arch/z80/src/ez80/ez80_rtc_lowerhalf.c
@@ -296,7 +296,7 @@ static int ez80_settime(FAR struct rtc_lowerhalf_s *lower,
    * rtc_time is cast compatible with struct tm.
    */
 
-  ts.tv_sec  = mktime((FAR struct tm *)rtctime);
+  ts.tv_sec  = timegm((FAR struct tm *)rtctime);
   ts.tv_nsec = 0;
 
   /* Now set the time (to one second accuracy) */
@@ -431,7 +431,7 @@ static int ez80_setrelative(FAR struct rtc_lowerhalf_s *lower,
     {
       /* Convert to seconds since the epoch */
 
-      seconds = mktime(&time);
+      seconds = timegm(&time);
 
       /* Add the seconds offset.  Add one to the number of seconds
        * because we are unsure of the phase of the timer.
diff --git a/drivers/timers/arch_rtc.c b/drivers/timers/arch_rtc.c
index 231f321acc9..6e1b90f3a12 100644
--- a/drivers/timers/arch_rtc.c
+++ b/drivers/timers/arch_rtc.c
@@ -89,7 +89,7 @@ time_t up_rtc_time(void)
 
       if (g_rtc_lower->ops->rdtime(g_rtc_lower, &rtctime) == 0)
         {
-          time = mktime((FAR struct tm *)&rtctime);
+          time = timegm((FAR struct tm *)&rtctime);
         }
     }
 
@@ -125,7 +125,7 @@ int up_rtc_gettime(FAR struct timespec *tp)
       ret = g_rtc_lower->ops->rdtime(g_rtc_lower, &rtctime);
       if (ret == 0)
         {
-          tp->tv_sec = mktime((FAR struct tm *)&rtctime);
+          tp->tv_sec = timegm((FAR struct tm *)&rtctime);
           tp->tv_nsec = rtctime.tm_nsec;
         }
     }
diff --git a/drivers/timers/rpmsg_rtc.c b/drivers/timers/rpmsg_rtc.c
index f0b3542399b..78b68d52026 100644
--- a/drivers/timers/rpmsg_rtc.c
+++ b/drivers/timers/rpmsg_rtc.c
@@ -367,7 +367,7 @@ static int rpmsg_rtc_settime(FAR struct rtc_lowerhalf_s *lower,
 {
   struct rpmsg_rtc_set_s msg =
   {
-    .sec  = mktime((FAR struct tm *)rtctime),
+    .sec  = timegm((FAR struct tm *)rtctime),
     .nsec = rtctime->tm_nsec,
   };
 
@@ -388,7 +388,7 @@ static int rpmsg_rtc_setalarm(FAR struct rtc_lowerhalf_s *lower_,
     (FAR struct rpmsg_rtc_lowerhalf_s *)lower_;
   struct rpmsg_rtc_alarm_set_s msg =
   {
-    .sec  = mktime((FAR struct tm *)&alarminfo->time),
+    .sec  = timegm((FAR struct tm *)&alarminfo->time),
     .nsec = alarminfo->time.tm_nsec,
     .id   = alarminfo->id,
   };
@@ -419,7 +419,7 @@ rpmsg_rtc_setrelative(FAR struct rtc_lowerhalf_s *lower,
   time_t time;
 
   rpmsg_rtc_rdtime(lower, &alarminfo.time);
-  time = mktime((FAR struct tm *)&alarminfo.time);
+  time = timegm((FAR struct tm *)&alarminfo.time);
   time = time + relinfo->reltime;
   gmtime_r(&time, (FAR struct tm *)&alarminfo.time);
 
diff --git a/fs/fat/fs_fat32util.c b/fs/fat/fs_fat32util.c
index c69cc9d3775..1b758e87a70 100644
--- a/fs/fat/fs_fat32util.c
+++ b/fs/fat/fs_fat32util.c
@@ -465,7 +465,7 @@ time_t fat_fattime2systime(uint16_t fattime, uint16_t fatdate)
 
   /* Then convert the broken out time into seconds since the epoch */
 
-  return mktime(&tm);
+  return timegm(&tm);
 #else
   return 0;
 #endif
diff --git a/sched/clock/clock_initialize.c b/sched/clock/clock_initialize.c
index 223e81bb954..7edafb7c96b 100644
--- a/sched/clock/clock_initialize.c
+++ b/sched/clock/clock_initialize.c
@@ -92,7 +92,7 @@ int clock_basetime(FAR struct timespec *tp)
     {
       /* And use the broken-out time to initialize the system time */
 
-      tp->tv_sec  = mktime(&rtctime);
+      tp->tv_sec  = timegm(&rtctime);
       tp->tv_nsec = nsecs;
     }