diff --git a/libs/libc/time/lib_strftime.c b/libs/libc/time/lib_strftime.c
index 43be9a03d8..f8342c2d67 100644
--- a/libs/libc/time/lib_strftime.c
+++ b/libs/libc/time/lib_strftime.c
@@ -267,7 +267,8 @@ size_t strftime(FAR char *s, size_t max, FAR const char *format,
 
            case 'I':
              {
-               len = snprintf(dest, chleft, "%02d", tm->tm_hour % 12);
+               len = snprintf(dest, chleft, "%02d", (tm->tm_hour % 12) != 0 ?
+                                                    (tm->tm_hour % 12) : 12);
              }
              break;