diff --git a/oslo_utils/tests/test_timeutils.py b/oslo_utils/tests/test_timeutils.py
index 4e24adbf..1178f1d0 100644
--- a/oslo_utils/tests/test_timeutils.py
+++ b/oslo_utils/tests/test_timeutils.py
@@ -203,6 +203,12 @@ class TimeUtilsTest(test_base.BaseTestCase):
         ts = calendar.timegm(utcnow.timetuple())
         self.assertEqual(iso, timeutils.iso8601_from_timestamp(ts))
 
+    def test_iso8601_from_timestamp_ms(self):
+        ts = timeutils.utcnow_ts(microsecond=True)
+        utcnow = datetime.datetime.utcfromtimestamp(ts)
+        iso = timeutils.isotime(utcnow, subsecond=True)
+        self.assertEqual(iso, timeutils.iso8601_from_timestamp(ts, True))
+
     def test_is_soon(self):
         expires = timeutils.utcnow() + datetime.timedelta(minutes=5)
         self.assertFalse(timeutils.is_soon(expires, 120))
diff --git a/oslo_utils/timeutils.py b/oslo_utils/timeutils.py
index adf1abd4..c7c3d622 100644
--- a/oslo_utils/timeutils.py
+++ b/oslo_utils/timeutils.py
@@ -130,9 +130,9 @@ def utcnow():
     return datetime.datetime.utcnow()
 
 
-def iso8601_from_timestamp(timestamp):
+def iso8601_from_timestamp(timestamp, microsecond=False):
     """Returns an iso8601 formatted date from timestamp."""
-    return isotime(datetime.datetime.utcfromtimestamp(timestamp))
+    return isotime(datetime.datetime.utcfromtimestamp(timestamp), microsecond)
 
 
 utcnow.override_time = None