diff --git a/oslo_utils/tests/test_timeutils.py b/oslo_utils/tests/test_timeutils.py
index 5777c4d5..ea0b5c1c 100644
--- a/oslo_utils/tests/test_timeutils.py
+++ b/oslo_utils/tests/test_timeutils.py
@@ -112,6 +112,11 @@ def test_is_older_than_aware(self):
         self._test_is_older_than(lambda x: x.replace(
             tzinfo=iso8601.iso8601.UTC))
 
+    def test_is_older_than_aware_no_utc(self):
+        self._test_is_older_than(lambda x: x.replace(
+            tzinfo=iso8601.iso8601.FixedOffset(1, 0, 'foo')).replace(
+                hour=7))
+
     def _test_is_newer_than(self, fn):
         strptime = datetime.datetime.strptime
         with mock.patch('datetime.datetime') as datetime_mock:
@@ -138,6 +143,11 @@ def test_is_newer_than_aware(self):
         self._test_is_newer_than(lambda x: x.replace(
             tzinfo=iso8601.iso8601.UTC))
 
+    def test_is_newer_than_aware_no_utc(self):
+        self._test_is_newer_than(lambda x: x.replace(
+            tzinfo=iso8601.iso8601.FixedOffset(1, 0, 'foo')).replace(
+                hour=7))
+
     def test_set_time_override_using_default(self):
         now = timeutils.utcnow_ts()
 
diff --git a/oslo_utils/timeutils.py b/oslo_utils/timeutils.py
index 2b9e996d..17495e49 100644
--- a/oslo_utils/timeutils.py
+++ b/oslo_utils/timeutils.py
@@ -119,9 +119,9 @@ def normalize_time(timestamp):
 def is_older_than(before, seconds):
     """Return True if before is older than seconds."""
     if isinstance(before, six.string_types):
-        before = parse_isotime(before).replace(tzinfo=None)
-    else:
-        before = before.replace(tzinfo=None)
+        before = parse_isotime(before)
+
+    before = normalize_time(before)
 
     return utcnow() - before > datetime.timedelta(seconds=seconds)
 
@@ -129,9 +129,9 @@ def is_older_than(before, seconds):
 def is_newer_than(after, seconds):
     """Return True if after is newer than seconds."""
     if isinstance(after, six.string_types):
-        after = parse_isotime(after).replace(tzinfo=None)
-    else:
-        after = after.replace(tzinfo=None)
+        after = parse_isotime(after)
+
+    after = normalize_time(after)
 
     return after - utcnow() > datetime.timedelta(seconds=seconds)