diff --git a/gcalcli/actions.py b/gcalcli/actions.py
index 18f887bd..8fbd69e9 100644
--- a/gcalcli/actions.py
+++ b/gcalcli/actions.py
@@ -1,8 +1,7 @@
 """Handlers for specific agendaupdate actions."""
 
-from gcalcli.details import FIELD_HANDLERS, FIELDNAMES_READONLY
-from gcalcli.exceptions import ReadonlyError
-
+from .details import FIELD_HANDLERS, FIELDNAMES_READONLY
+from .exceptions import ReadonlyError
 
 CONFERENCE_DATA_VERSION = 1
 
diff --git a/gcalcli/argparsers.py b/gcalcli/argparsers.py
index 858b4a5f..1d56878c 100644
--- a/gcalcli/argparsers.py
+++ b/gcalcli/argparsers.py
@@ -1,17 +1,21 @@
 from __future__ import absolute_import
+
 import argparse
-import gcalcli
-from gcalcli import utils
-from gcalcli.details import DETAILS
-from gcalcli.deprecations import parser_allow_deprecated, DeprecatedStoreTrue
-from gcalcli.printer import valid_color_name
-from oauth2client import tools
-from shutil import get_terminal_size
 import copy as _copy
 import datetime
 import locale
+from shutil import get_terminal_size
 import sys
 
+from oauth2client import tools
+
+import gcalcli
+
+from . import utils
+from .deprecations import DeprecatedStoreTrue, parser_allow_deprecated
+from .details import DETAILS
+from .printer import valid_color_name
+
 PROGRAM_OPTIONS = {
         '--client-id': {'default': gcalcli.__API_CLIENT_ID__,
                         'type': str,
diff --git a/gcalcli/cli.py b/gcalcli/cli.py
index 99b82dd4..f36dc4f0 100755
--- a/gcalcli/cli.py
+++ b/gcalcli/cli.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-#############################################################################
+# ######################################################################### #
 #                                                                           #
 #                                      (           (     (                  #
 #               (         (     (      )\ )   (    )\ )  )\ )               #
@@ -18,21 +18,19 @@
 #                                                                           #
 # Everything you need to know (Google API Calendar v3): http://goo.gl/HfTGQ #
 #                                                                           #
-#############################################################################
+# ######################################################################### #
+from collections import namedtuple
 import os
 import signal
 import sys
-from collections import namedtuple
 
-from gcalcli import utils
-from gcalcli.argparsers import get_argument_parser, handle_unparsed
-from gcalcli.exceptions import GcalcliError
-from gcalcli.gcal import GoogleCalendarInterface
-from gcalcli.printer import Printer, valid_color_name
-from gcalcli.validators import (
-        PARSABLE_DATE, REMINDER, STR_ALLOW_EMPTY, STR_NOT_EMPTY,
-        PARSABLE_DURATION, get_input
-)
+from . import utils
+from .argparsers import get_argument_parser, handle_unparsed
+from .exceptions import GcalcliError
+from .gcal import GoogleCalendarInterface
+from .printer import Printer, valid_color_name
+from .validators import (get_input, PARSABLE_DATE, PARSABLE_DURATION, REMINDER,
+                         STR_ALLOW_EMPTY, STR_NOT_EMPTY)
 
 CalName = namedtuple('CalName', ['name', 'color'])
 
diff --git a/gcalcli/deprecations.py b/gcalcli/deprecations.py
index b89c238c..6c643c11 100644
--- a/gcalcli/deprecations.py
+++ b/gcalcli/deprecations.py
@@ -2,8 +2,8 @@
 import functools
 
 import gcalcli
-from gcalcli.printer import valid_color_name, Printer
 
+from .printer import Printer, valid_color_name
 
 printer = Printer()
 
diff --git a/gcalcli/details.py b/gcalcli/details.py
index 8cfd6b6b..d5a408ea 100644
--- a/gcalcli/details.py
+++ b/gcalcli/details.py
@@ -3,12 +3,12 @@
 from collections import OrderedDict
 from datetime import datetime
 from itertools import chain
-from typing import List
+from typing import List  # python3.9: can just use `list`
 
 from dateutil.parser import isoparse, parse
 
-from gcalcli.exceptions import ReadonlyError, ReadonlyCheckError
-from gcalcli.utils import is_all_day
+from .exceptions import ReadonlyCheckError, ReadonlyError
+from .utils import is_all_day
 
 FMT_DATE = '%Y-%m-%d'
 FMT_TIME = '%H:%M'
@@ -33,8 +33,7 @@ class Handler:
     """Handler for a specific detail of an event."""
 
     # list of strings for fieldnames provided by this object
-    # XXX: py36+: change to `fieldnames: List[str]`
-    fieldnames = []  # type: List[str]
+    fieldnames: List[str] = []
 
     @classmethod
     def get(cls, event):
diff --git a/gcalcli/gcal.py b/gcalcli/gcal.py
index 098357ab..65b512d3 100644
--- a/gcalcli/gcal.py
+++ b/gcalcli/gcal.py
@@ -1,44 +1,43 @@
+from collections import namedtuple
 from csv import DictReader, excel_tab
-import os
-import re
-import shlex
-import httplib2
+from datetime import date, datetime, timedelta
 from itertools import chain
-import time
-import textwrap
 import json
+import os
 import random
+import re
+import shlex
 import sys
+import textwrap
+import time
 from unicodedata import east_asian_width
+
+from apiclient.discovery import build
+from apiclient.errors import HttpError
+from dateutil.parser import parse
+from dateutil.relativedelta import relativedelta
+from dateutil.tz import tzlocal
+import httplib2
+from oauth2client import tools
+from oauth2client.client import OAuth2WebServerFlow
+from oauth2client.file import Storage
+
+from . import __program__, __version__, actions, utils
+from .actions import ACTIONS
+from .conflicts import ShowConflicts
+from .details import _valid_title, ACTION_DEFAULT, DETAILS_DEFAULT, HANDLERS
+from .exceptions import GcalcliError
+from .printer import Printer
+from .utils import days_since_epoch, is_all_day
+from .validators import (get_input, get_override_color_id, PARSABLE_DATE,
+                         PARSABLE_DURATION, REMINDER, STR_ALLOW_EMPTY,
+                         STR_NOT_EMPTY, STR_TO_INT, VALID_COLORS)
+
 try:
     import cPickle as pickle
 except Exception:
     import pickle
 
-from gcalcli import __program__, __version__
-from gcalcli import actions, utils
-from gcalcli.actions import ACTIONS
-from gcalcli.details import (
-    _valid_title, ACTION_DEFAULT, DETAILS_DEFAULT, HANDLERS)
-from gcalcli.utils import days_since_epoch, is_all_day
-from gcalcli.validators import (
-    get_input, get_override_color_id, STR_NOT_EMPTY, PARSABLE_DATE, STR_TO_INT,
-    VALID_COLORS, STR_ALLOW_EMPTY, REMINDER, PARSABLE_DURATION
-)
-from gcalcli.exceptions import GcalcliError
-from gcalcli.printer import Printer
-from gcalcli.conflicts import ShowConflicts
-
-from dateutil.relativedelta import relativedelta
-from datetime import datetime, timedelta, date
-from dateutil.tz import tzlocal
-from dateutil.parser import parse
-from apiclient.discovery import build
-from apiclient.errors import HttpError
-from oauth2client.file import Storage
-from oauth2client.client import OAuth2WebServerFlow
-from oauth2client import tools
-from collections import namedtuple
 
 EventTitle = namedtuple('EventTitle', ['title', 'color'])
 
diff --git a/gcalcli/utils.py b/gcalcli/utils.py
index 86ece362..8d87500d 100644
--- a/gcalcli/utils.py
+++ b/gcalcli/utils.py
@@ -1,13 +1,13 @@
 import calendar
-import time
+from datetime import datetime, timedelta
 import locale
 import re
-from dateutil.tz import tzlocal
+import time
+
 from dateutil.parser import parse as dateutil_parse
-from datetime import datetime, timedelta
+from dateutil.tz import tzlocal
 from parsedatetime.parsedatetime import Calendar
 
-
 locale.setlocale(locale.LC_ALL, '')
 fuzzy_date_parse = Calendar().parse
 fuzzy_datetime_parse = Calendar().parseDT
diff --git a/gcalcli/validators.py b/gcalcli/validators.py
index bd8e9ccd..437ed58d 100644
--- a/gcalcli/validators.py
+++ b/gcalcli/validators.py
@@ -1,8 +1,7 @@
 import re
 
-from gcalcli.exceptions import ValidationError
-from gcalcli.utils import (REMINDER_REGEX, get_time_from_str,
-                           get_timedelta_from_str)
+from .exceptions import ValidationError
+from .utils import get_time_from_str, get_timedelta_from_str, REMINDER_REGEX
 
 # TODO: in the future, pull these from the API
 # https://developers.google.com/calendar/v3/reference/colors
diff --git a/setup.cfg b/setup.cfg
index 2a9acf13..6a9c3ba8 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,2 +1,12 @@
 [bdist_wheel]
 universal = 1
+
+[flake8]
+import-order-style = google
+
+[isort]
+profile=google
+force_single_line=False
+float_to_top=True
+combine_star=True
+py_version=3
diff --git a/setup.py b/setup.py
old mode 100644
new mode 100755
index 929ae2a1..1c0eb6d7
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 from setuptools import setup
+
 from gcalcli import __version__
 
 try:
diff --git a/tests/conftest.py b/tests/conftest.py
index 2daa97fb..96f95537 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,15 +1,12 @@
+from datetime import datetime
 import os
 import sys
 
-import pytest
-
-from datetime import datetime
+from apiclient.discovery import build, HttpMock
 from dateutil.tz import tzlocal
+import pytest
 
-from apiclient.discovery import HttpMock, build
-
-from gcalcli.argparsers import (get_color_parser,
-                                get_cal_query_parser,
+from gcalcli.argparsers import (get_cal_query_parser, get_color_parser,
                                 get_output_parser)
 from gcalcli.gcal import GoogleCalendarInterface
 from gcalcli.printer import Printer
diff --git a/tests/test_argparsers.py b/tests/test_argparsers.py
index 03ab5562..5c4c6800 100644
--- a/tests/test_argparsers.py
+++ b/tests/test_argparsers.py
@@ -1,8 +1,10 @@
-from gcalcli import argparsers
 from collections import namedtuple
 import shlex
+
 import pytest
 
+from gcalcli import argparsers
+
 
 def test_get_argparser():
     """Just asserts no errors have been introduced"""
diff --git a/tests/test_cli.py b/tests/test_cli.py
index e85752cb..ef3482d7 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -1,5 +1,6 @@
-from gcalcli.cli import run_add_prompt
 from argparse import Namespace
+
+from gcalcli.cli import run_add_prompt
 from gcalcli.printer import Printer
 
 
diff --git a/tests/test_conflicts.py b/tests/test_conflicts.py
index 6d390de1..65480f1e 100644
--- a/tests/test_conflicts.py
+++ b/tests/test_conflicts.py
@@ -1,7 +1,9 @@
-from gcalcli.conflicts import ShowConflicts
 from datetime import datetime
+
 from dateutil.tz import tzlocal
 
+from gcalcli.conflicts import ShowConflicts
+
 minimal_event = {
                     'e': datetime(2019, 1, 8, 15, 15, tzinfo=tzlocal()),
                     'id': 'minimial_event',
diff --git a/tests/test_gcalcli.py b/tests/test_gcalcli.py
index dddf86e9..e0069238 100644
--- a/tests/test_gcalcli.py
+++ b/tests/test_gcalcli.py
@@ -1,22 +1,18 @@
 from __future__ import absolute_import
 
-import os
+from datetime import datetime
 from json import load
+import os
 
 from dateutil.tz import tzutc
-from datetime import datetime
 
-from gcalcli.utils import parse_reminder
-from gcalcli.argparsers import (get_start_end_parser,
-                                get_color_parser,
-                                get_cal_query_parser,
-                                get_output_parser,
-                                get_updates_parser,
-                                get_conflicts_parser,
-                                get_search_parser)
-from gcalcli.gcal import GoogleCalendarInterface
+from gcalcli.argparsers import (get_cal_query_parser, get_color_parser,
+                                get_conflicts_parser, get_output_parser,
+                                get_search_parser, get_start_end_parser,
+                                get_updates_parser)
 from gcalcli.cli import parse_cal_names
-
+from gcalcli.gcal import GoogleCalendarInterface
+from gcalcli.utils import parse_reminder
 
 TEST_DATA_DIR = os.path.dirname(os.path.abspath(__file__)) + '/data'
 
diff --git a/tests/test_input_validation.py b/tests/test_input_validation.py
index f1d60deb..ec0fd6b7 100644
--- a/tests/test_input_validation.py
+++ b/tests/test_input_validation.py
@@ -1,13 +1,9 @@
 import pytest
 
-from gcalcli.validators import validate_input, ValidationError
-from gcalcli.validators import (STR_NOT_EMPTY,
-                                PARSABLE_DATE,
-                                PARSABLE_DURATION,
-                                STR_TO_INT,
-                                STR_ALLOW_EMPTY,
-                                REMINDER,
-                                VALID_COLORS)
+from gcalcli.validators import (PARSABLE_DATE, PARSABLE_DURATION, REMINDER,
+                                STR_ALLOW_EMPTY, STR_NOT_EMPTY, STR_TO_INT,
+                                VALID_COLORS, validate_input, ValidationError)
+
 # Tests required:
 #
 # * Title: any string, not blank
diff --git a/tests/test_printer.py b/tests/test_printer.py
index 9e420717..2aa7a17d 100644
--- a/tests/test_printer.py
+++ b/tests/test_printer.py
@@ -1,8 +1,9 @@
-import sys
 from argparse import ArgumentTypeError
 from io import StringIO
+import sys
 
 import pytest
+
 from gcalcli.printer import COLOR_NAMES, Printer, valid_color_name
 
 
diff --git a/tests/test_utils.py b/tests/test_utils.py
index b47f496f..59ff1e39 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,8 +1,10 @@
-import gcalcli.utils as utils
 from datetime import datetime, timedelta
+
 from dateutil.tz import UTC
 import pytest
 
+import gcalcli.utils as utils
+
 
 def test_get_time_from_str():
     assert utils.get_time_from_str('7am tomorrow')