diff --git a/setup.py b/setup.py
index eff4c2b..0fbad77 100644
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-from setuptools import setup, find_packages
+from setuptools import find_packages, setup
 
 install_requires = [
     'pytz',
diff --git a/stix2/bundle.py b/stix2/bundle.py
index 5785d43..85be3e1 100644
--- a/stix2/bundle.py
+++ b/stix2/bundle.py
@@ -1,7 +1,7 @@
 """STIX 2 Bundle object"""
 
 from .base import _STIXBase
-from .properties import IDProperty, TypeProperty, Property
+from .properties import IDProperty, Property, TypeProperty
 
 
 class Bundle(_STIXBase):
diff --git a/stix2/common.py b/stix2/common.py
index a541b09..29cbf62 100644
--- a/stix2/common.py
+++ b/stix2/common.py
@@ -1,8 +1,8 @@
 """STIX 2 Common Data Types and Properties"""
 
-from .properties import (ListProperty, BooleanProperty,
-                         ReferenceProperty, TimestampProperty)
 from .other import ExternalReference, GranularMarking
+from .properties import (BooleanProperty, ListProperty, ReferenceProperty,
+                         TimestampProperty)
 from .utils import NOW
 
 COMMON_PROPERTIES = {
diff --git a/stix2/other.py b/stix2/other.py
index d8d5f1d..9b7f03a 100644
--- a/stix2/other.py
+++ b/stix2/other.py
@@ -1,10 +1,10 @@
 """STIX 2.0 Objects that are neither SDOs nor SROs"""
 
 from .base import _STIXBase
-from .properties import (IDProperty, TypeProperty, ListProperty, TimestampProperty,
-                         ReferenceProperty, Property, SelectorProperty,
-                         StringProperty)
-from .utils import NOW, get_dict
+from .properties import (IDProperty, ListProperty, Property, ReferenceProperty,
+                         SelectorProperty, StringProperty, TimestampProperty,
+                         TypeProperty)
+from .utils import get_dict, NOW
 
 
 class ExternalReference(_STIXBase):
diff --git a/stix2/properties.py b/stix2/properties.py
index 07b84a9..ecdbf18 100644
--- a/stix2/properties.py
+++ b/stix2/properties.py
@@ -1,11 +1,13 @@
+import collections
+import datetime as dt
+import inspect
 import re
 import uuid
-from six import text_type
-import datetime as dt
-import pytz
+
 from dateutil import parser
-import inspect
-import collections
+import pytz
+from six import text_type
+
 from .base import _STIXBase
 
 
diff --git a/stix2/sdo.py b/stix2/sdo.py
index 105786b..693b750 100644
--- a/stix2/sdo.py
+++ b/stix2/sdo.py
@@ -3,9 +3,9 @@
 from .base import _STIXBase
 from .common import COMMON_PROPERTIES
 from .other import KillChainPhase
-from .properties import (Property, ListProperty, StringProperty, TypeProperty,
-                         IDProperty, TimestampProperty, ReferenceProperty,
-                         IntegerProperty)
+from .properties import (IDProperty, IntegerProperty, ListProperty, Property,
+                         ReferenceProperty, StringProperty, TimestampProperty,
+                         TypeProperty)
 from .utils import NOW
 
 
diff --git a/stix2/sro.py b/stix2/sro.py
index 30feef9..c13fff3 100644
--- a/stix2/sro.py
+++ b/stix2/sro.py
@@ -2,9 +2,9 @@
 
 from .base import _STIXBase
 from .common import COMMON_PROPERTIES
-from .properties import (ListProperty, StringProperty, TypeProperty,
-                         IDProperty, TimestampProperty, ReferenceProperty,
-                         IntegerProperty)
+from .properties import (IDProperty, IntegerProperty, ListProperty,
+                         ReferenceProperty, StringProperty, TimestampProperty,
+                         TypeProperty)
 
 
 class Relationship(_STIXBase):
diff --git a/stix2/test/test_attack_pattern.py b/stix2/test/test_attack_pattern.py
index 33be679..c0891a5 100644
--- a/stix2/test/test_attack_pattern.py
+++ b/stix2/test/test_attack_pattern.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import ATTACK_PATTERN_ID
diff --git a/stix2/test/test_campaign.py b/stix2/test/test_campaign.py
index e1bec3b..7f6c4e6 100644
--- a/stix2/test/test_campaign.py
+++ b/stix2/test/test_campaign.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import CAMPAIGN_ID
diff --git a/stix2/test/test_course_of_action.py b/stix2/test/test_course_of_action.py
index 3626539..f566e10 100644
--- a/stix2/test/test_course_of_action.py
+++ b/stix2/test/test_course_of_action.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import COURSE_OF_ACTION_ID
diff --git a/stix2/test/test_external_reference.py b/stix2/test/test_external_reference.py
index 5d46f87..f8d9b66 100644
--- a/stix2/test/test_external_reference.py
+++ b/stix2/test/test_external_reference.py
@@ -1,8 +1,8 @@
 """Tests for stix.ExternalReference"""
 
-import pytest
 import re
 
+import pytest
 import stix2
 
 VERIS = """{
diff --git a/stix2/test/test_identity.py b/stix2/test/test_identity.py
index 00726c9..41c87bb 100644
--- a/stix2/test/test_identity.py
+++ b/stix2/test/test_identity.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import IDENTITY_ID
diff --git a/stix2/test/test_indicator.py b/stix2/test/test_indicator.py
index dfa04b2..1c2b610 100644
--- a/stix2/test/test_indicator.py
+++ b/stix2/test/test_indicator.py
@@ -1,9 +1,8 @@
 import datetime as dt
+import re
 
 import pytest
 import pytz
-import re
-
 import stix2
 
 from .constants import FAKE_TIME, INDICATOR_ID, INDICATOR_KWARGS
diff --git a/stix2/test/test_intrusion_set.py b/stix2/test/test_intrusion_set.py
index e6cf1cf..19fb641 100644
--- a/stix2/test/test_intrusion_set.py
+++ b/stix2/test/test_intrusion_set.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import INTRUSION_SET_ID
diff --git a/stix2/test/test_malware.py b/stix2/test/test_malware.py
index 0006ef2..edc35b6 100644
--- a/stix2/test/test_malware.py
+++ b/stix2/test/test_malware.py
@@ -1,9 +1,8 @@
 import datetime as dt
+import re
 
 import pytest
 import pytz
-import re
-
 import stix2
 
 from .constants import FAKE_TIME, MALWARE_ID, MALWARE_KWARGS
@@ -148,3 +147,16 @@ def test_parse_malware_kill_chain_phases():
     assert mal.kill_chain_phases[0].phase_name == "reconnaissance"
     assert mal['kill_chain_phases'][0]['kill_chain_name'] == "lockheed-martin-cyber-kill-chain"
     assert mal['kill_chain_phases'][0]['phase_name'] == "reconnaissance"
+
+
+def test_parse_malware_clean_kill_chain_phases():
+    kill_chain = """
+      "kill_chain_phases": [
+        {
+          "kill_chain_name": "lockheed-martin-cyber-kill-chain",
+          "phase_name": 1
+        }
+      ]"""
+    data = EXPECTED_MALWARE.replace('malware"', 'malware",%s' % kill_chain)
+    mal = stix2.parse(data)
+    assert mal['kill_chain_phases'][0]['phase_name'] == "1"
diff --git a/stix2/test/test_markings.py b/stix2/test/test_markings.py
index c23abcb..b3cc479 100644
--- a/stix2/test/test_markings.py
+++ b/stix2/test/test_markings.py
@@ -1,8 +1,9 @@
-import stix2
-from stix2.other import TLP_WHITE
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
+import stix2
+from stix2.other import TLP_WHITE
 
 from .constants import MARKING_DEFINITION_ID
 
diff --git a/stix2/test/test_observed_data.py b/stix2/test/test_observed_data.py
index f4243e2..52dc15b 100644
--- a/stix2/test/test_observed_data.py
+++ b/stix2/test/test_observed_data.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import OBSERVED_DATA_ID
diff --git a/stix2/test/test_properties.py b/stix2/test/test_properties.py
index 7e9dc13..06172ab 100644
--- a/stix2/test/test_properties.py
+++ b/stix2/test/test_properties.py
@@ -1,9 +1,8 @@
 import pytest
 
-from stix2.properties import (Property, BooleanProperty, ListProperty,
-                              StringProperty, TypeProperty, IDProperty,
-                              IntegerProperty, ReferenceProperty,
-                              TimestampProperty)
+from stix2.properties import (BooleanProperty, IDProperty, IntegerProperty,
+                              ListProperty, Property, ReferenceProperty,
+                              StringProperty, TimestampProperty, TypeProperty)
 from .constants import FAKE_TIME
 
 
diff --git a/stix2/test/test_report.py b/stix2/test/test_report.py
index f28e607..46a0a16 100644
--- a/stix2/test/test_report.py
+++ b/stix2/test/test_report.py
@@ -1,7 +1,9 @@
-import stix2
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
+import stix2
+
 from .constants import INDICATOR_KWARGS, REPORT_ID
 
 EXPECTED = """{
diff --git a/stix2/test/test_threat_actor.py b/stix2/test/test_threat_actor.py
index 7eabbed..5844775 100644
--- a/stix2/test/test_threat_actor.py
+++ b/stix2/test/test_threat_actor.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import THREAT_ACTOR_ID
diff --git a/stix2/test/test_tool.py b/stix2/test/test_tool.py
index 0e4cd5c..3193807 100644
--- a/stix2/test/test_tool.py
+++ b/stix2/test/test_tool.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import TOOL_ID
diff --git a/stix2/test/test_vulnerability.py b/stix2/test/test_vulnerability.py
index bfa9c26..565f077 100644
--- a/stix2/test/test_vulnerability.py
+++ b/stix2/test/test_vulnerability.py
@@ -1,6 +1,7 @@
+import datetime as dt
+
 import pytest
 import pytz
-import datetime as dt
 import stix2
 
 from .constants import VULNERABILITY_ID
diff --git a/stix2/utils.py b/stix2/utils.py
index f91215b..cdc7f54 100644
--- a/stix2/utils.py
+++ b/stix2/utils.py
@@ -1,9 +1,10 @@
 """Utility functions and classes for the stix2 library."""
 
 import datetime as dt
-import pytz
 import json
 
+import pytz
+
 # Sentinel value for fields that should be set to the current time.
 # We can't use the standard 'default' approach, since if there are multiple
 # timestamps in a single object, the timestamps will vary by a few microseconds.
diff --git a/tox.ini b/tox.ini
index fd580f9..80213d7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,10 +8,11 @@ commands = pytest
 [testenv:pycodestyle]
 deps =
   flake8
+  flake8-import-order
   pycodestyle
 commands =
   pycodestyle ./stix2
-  flake8 --max-line-length=160
+  flake8 --max-line-length=160 --import-order-style='google'
 
 [pycodestyle]
 ignore=