diff --git a/libretro/libretro.c b/libretro/libretro.c
index 0fb8dc5..6b531b6 100644
--- a/libretro/libretro.c
+++ b/libretro/libretro.c
@@ -237,6 +237,7 @@ static const struct retro_variable vars_single[] = {
     { "sameboy_model", "Emulated model (Restart game); Auto|Game Boy|Game Boy Color|Game Boy Advance|Super Game Boy|Super Game Boy 2" },
     { "sameboy_border", "Display border; Super Game Boy only|always|never" },
     { "sameboy_rumble", "Enable rumble; rumble-enabled games|all games|never" },
+    { "sameboy_rtc", "Real Time Clock emulation; sync to system clock|accurate" },
     { NULL }
 };
 
@@ -594,6 +595,17 @@ static void check_variables()
                 GB_set_rumble_mode(&gameboy[0], GB_RUMBLE_ALL_GAMES);
             }
         }
+        
+        var.key = "sameboy_rtc";
+        var.value = NULL;
+        if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value) {
+            if (strcmp(var.value, "sync to system clock") == 0) {
+                GB_set_rtc_mode(&gameboy[0], GB_RTC_MODE_SYNC_TO_HOST);
+            }
+            else if (strcmp(var.value, "accurate") == 0) {
+                GB_set_rtc_mode(&gameboy[0], GB_RTC_MODE_ACCURATE);
+            }
+        }
 
         var.key = "sameboy_high_pass_filter_mode";
         var.value = NULL;
@@ -654,6 +666,8 @@ static void check_variables()
     else {
         GB_set_border_mode(&gameboy[0], GB_BORDER_NEVER);
         GB_set_border_mode(&gameboy[1], GB_BORDER_NEVER);
+        GB_set_rtc_mode(&gameboy[0], GB_RTC_MODE_ACCURATE);
+        GB_set_rtc_mode(&gameboy[1], GB_RTC_MODE_ACCURATE);
         var.key = "sameboy_color_correction_mode_1";
         var.value = NULL;
         if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value) {