diff --git a/mrbgems/mruby-time/src/time.c b/mrbgems/mruby-time/src/time.c
index 5165ad5cd..15028b3ea 100644
--- a/mrbgems/mruby-time/src/time.c
+++ b/mrbgems/mruby-time/src/time.c
@@ -1583,6 +1583,39 @@ time_saturday(mrb_state *mrb, mrb_value self)
   return time_wday_p(mrb, self, 6);
 }
 
+/*
+ * ISO 15.2.19.7.12
+ * ISO 15.2.19.7.14
+ * ISO 15.2.19.7.29
+ */
+/*
+ * call-seq:
+ *   time.gmt_offset  -> integer
+ *   time.utc_offset  -> integer
+ *   time.gmtoff      -> integer
+ *
+ * Returns the offset in seconds between the timezone of time and UTC.
+ *
+ *   Time.local(2000, 1, 1).gmt_offset   #=> 32400 (JST: UTC+9)
+ *   Time.utc(2000, 1, 1).utc_offset     #=> 0     (UTC)
+ *   Time.local(2000, 7, 1).gmtoff       #=> 32400 (or 28800 if DST)
+ */
+static mrb_value
+time_utc_offset(mrb_state *mrb, mrb_value self)
+{
+  struct mrb_time *tm = time_get_ptr(mrb, self);
+
+  if (tm->timezone == MRB_TIMEZONE_UTC) {
+    return mrb_fixnum_value(0);  /* UTC is always offset 0 */
+  }
+
+  /* For local times, calculate offset = local_time_t - utc_time_t */
+  time_t utc_time_t = timegm(&tm->datetime);  /* Convert datetime as UTC */
+  mrb_int offset_seconds = (mrb_int)(tm->sec - utc_time_t);
+
+  return mrb_fixnum_value(offset_seconds);
+}
+
 void
 mrb_mruby_time_gem_init(mrb_state* mrb)
 {
@@ -1656,12 +1689,9 @@ mrb_mruby_time_gem_init(mrb_state* mrb)
   mrb_define_method_id(mrb, tc, MRB_SYM_Q(friday), time_friday, MRB_ARGS_NONE());
   mrb_define_method_id(mrb, tc, MRB_SYM_Q(saturday), time_saturday, MRB_ARGS_NONE());
 
-  /*
-    methods not available:
-      gmt_offset(15.2.19.7.12)
-      gmtoff(15.2.19.7.14)
-      utc_offset(15.2.19.7.29)
-  */
+  mrb_define_method_id(mrb, tc, MRB_SYM(gmt_offset), time_utc_offset, MRB_ARGS_NONE()); /* 15.2.19.7.12 */
+  mrb_define_method_id(mrb, tc, MRB_SYM(gmtoff), time_utc_offset, MRB_ARGS_NONE());    /* 15.2.19.7.14 */
+  mrb_define_method_id(mrb, tc, MRB_SYM(utc_offset), time_utc_offset, MRB_ARGS_NONE()); /* 15.2.19.7.29 */
 }
 
 void
diff --git a/mrbgems/mruby-time/test/time.rb b/mrbgems/mruby-time/test/time.rb
index 2c3a354f4..c450e424d 100644
--- a/mrbgems/mruby-time/test/time.rb
+++ b/mrbgems/mruby-time/test/time.rb
@@ -219,8 +219,24 @@ assert('Time#utc?', '15.2.19.7.28') do
   assert_predicate(Time.at(1300000000).utc, :utc?)
 end
 
-# ATM not implemented
-# assert('Time#utc_offset', '15.2.19.7.29') do
+assert('Time#utc_offset, #gmt_offset, #gmtoff', '15.2.19.7.12, 15.2.19.7.14, 15.2.19.7.29') do
+  # UTC times should have zero offset
+  utc_time = Time.utc(2000, 1, 1)
+  assert_equal(0, utc_time.utc_offset)
+
+  # Local times should return integer offsets in seconds
+  local_time = Time.local(2000, 1, 1)
+  assert_kind_of(Integer, local_time.utc_offset)
+
+  # Test that offset values make sense (should be multiple of 900 seconds = 15 minutes)
+  assert_equal(0, local_time.utc_offset % 900)
+
+  # All three methods should be aliases returning identical values
+  assert_equal(utc_time.utc_offset, utc_time.gmt_offset)
+  assert_equal(utc_time.utc_offset, utc_time.gmtoff)
+  assert_equal(local_time.utc_offset, local_time.gmt_offset)
+  assert_equal(local_time.utc_offset, local_time.gmtoff)
+end
 
 assert('Time#wday', '15.2.19.7.30') do
   assert_equal(0, Time.gm(2012, 12, 23).wday)