diff --git a/refstack/api/app.py b/refstack/api/app.py
index f88afb11..b43bcf68 100644
--- a/refstack/api/app.py
+++ b/refstack/api/app.py
@@ -23,7 +23,6 @@ from beaker.middleware import SessionMiddleware
 from oslo_config import cfg
 from oslo_log import log
 import pecan
-import six
 import webob
 
 from refstack.api import exceptions as api_exc
@@ -159,7 +158,7 @@ class JSONErrorHook(pecan.hooks.PecanHook):
 
         body = {'title': title or exc.args[0], 'code': status_code}
         if self.debug:
-            body['detail'] = six.text_type(exc)
+            body['detail'] = str(exc)
         return webob.Response(
             body=json.dumps(body),
             status=status_code,
diff --git a/refstack/api/controllers/auth.py b/refstack/api/controllers/auth.py
index 178220fa..012a675a 100644
--- a/refstack/api/controllers/auth.py
+++ b/refstack/api/controllers/auth.py
@@ -18,7 +18,7 @@
 from oslo_config import cfg
 import pecan
 from pecan import rest
-from six.moves.urllib import parse
+from urllib import parse
 
 from refstack.api import constants as const
 from refstack.api import utils as api_utils
diff --git a/refstack/api/controllers/products.py b/refstack/api/controllers/products.py
index 7e1ca971..e2d5e995 100644
--- a/refstack/api/controllers/products.py
+++ b/refstack/api/controllers/products.py
@@ -22,7 +22,6 @@ from oslo_db.exception import DBReferenceError
 from oslo_log import log
 import pecan
 from pecan.secure import secure
-import six
 
 from refstack.api import constants as const
 from refstack.api.controllers import validation
@@ -222,7 +221,7 @@ class ProductsController(validation.BaseRestControllerWithValidation):
                            if product['product_type'] == const.DISTRO
                            else const.CLOUD)
         if product['type'] == const.SOFTWARE:
-            product['product_ref_id'] = six.text_type(uuid.uuid4())
+            product['product_ref_id'] = str(uuid.uuid4())
         vendor_id = product.pop('organization_id', None)
         if not vendor_id:
             # find or create default vendor for new product
diff --git a/refstack/api/controllers/results.py b/refstack/api/controllers/results.py
index 010b33db..79cdeb8a 100644
--- a/refstack/api/controllers/results.py
+++ b/refstack/api/controllers/results.py
@@ -21,7 +21,7 @@ from oslo_log import log
 import pecan
 from pecan import rest
 
-from six.moves.urllib import parse
+from urllib import parse
 
 from refstack import db
 from refstack.api import constants as const
diff --git a/refstack/api/controllers/vendors.py b/refstack/api/controllers/vendors.py
index 443546dd..d55f4c79 100644
--- a/refstack/api/controllers/vendors.py
+++ b/refstack/api/controllers/vendors.py
@@ -16,7 +16,6 @@
 
 import base64
 import json
-import six
 
 from oslo_config import cfg
 from oslo_db.exception import DBReferenceError
@@ -55,7 +54,7 @@ class UsersController(rest.RestController):
             return None
 
         org_users = db.get_organization_users(vendor_id)
-        return [x for x in six.itervalues(org_users)]
+        return [x for x in org_users.values()]
 
     @secure(api_utils.is_authenticated)
     @pecan.expose('json')
diff --git a/refstack/api/utils.py b/refstack/api/utils.py
index 44699e19..c31b306b 100644
--- a/refstack/api/utils.py
+++ b/refstack/api/utils.py
@@ -31,7 +31,7 @@ import pecan
 import pecan.rest
 import jwt
 
-from six.moves.urllib import parse
+from urllib import parse
 
 from refstack import db
 from refstack.api import constants as const
diff --git a/refstack/api/validators.py b/refstack/api/validators.py
index 02602803..1b797ad4 100644
--- a/refstack/api/validators.py
+++ b/refstack/api/validators.py
@@ -16,7 +16,6 @@
 """Validators module."""
 
 import binascii
-import six
 import uuid
 
 import json
@@ -79,7 +78,7 @@ class BaseValidator(object):
         """Check that all values are not empty."""
         for key in keys:
             value = body[key]
-            if isinstance(value, six.string_types):
+            if isinstance(value, str):
                 value = value.strip()
                 if not value:
                     raise api_exc.ValidationError(key + ' should not be empty')
diff --git a/refstack/db/sqlalchemy/models.py b/refstack/db/sqlalchemy/models.py
index 0d8ef073..f0c2b8a9 100644
--- a/refstack/db/sqlalchemy/models.py
+++ b/refstack/db/sqlalchemy/models.py
@@ -19,7 +19,6 @@
 import uuid
 
 from oslo_db.sqlalchemy import models
-import six
 import sqlalchemy as sa
 from sqlalchemy import orm
 from sqlalchemy.ext.declarative import declarative_base
@@ -151,7 +150,7 @@ class PubKey(BASE, RefStackBase):  # pragma: no cover
     __tablename__ = 'pubkeys'
 
     id = sa.Column(sa.String(36), primary_key=True,
-                   default=lambda: six.text_type(uuid.uuid4()))
+                   default=lambda: str(uuid.uuid4()))
     openid = sa.Column(sa.String(128), sa.ForeignKey('user.openid'),
                        nullable=False, unique=True, index=True)
     format = sa.Column(sa.String(24), nullable=False)
@@ -171,7 +170,7 @@ class Group(BASE, RefStackBase):  # pragma: no cover
     __tablename__ = 'group'
 
     id = sa.Column(sa.String(36), primary_key=True,
-                   default=lambda: six.text_type(uuid.uuid4()))
+                   default=lambda: str(uuid.uuid4()))
     name = sa.Column(sa.String(80), nullable=False)
     description = sa.Column(sa.Text())
 
@@ -205,7 +204,7 @@ class Organization(BASE, RefStackBase):  # pragma: no cover
     __tablename__ = 'organization'
 
     id = sa.Column(sa.String(36), primary_key=True,
-                   default=lambda: six.text_type(uuid.uuid4()))
+                   default=lambda: str(uuid.uuid4()))
     type = sa.Column(sa.Integer, nullable=False)
     name = sa.Column(sa.String(80), nullable=False)
     description = sa.Column(sa.Text())
@@ -228,7 +227,7 @@ class Product(BASE, RefStackBase):  # pragma: no cover
     __tablename__ = 'product'
 
     id = sa.Column(sa.String(36), primary_key=True,
-                   default=lambda: six.text_type(uuid.uuid4()))
+                   default=lambda: str(uuid.uuid4()))
     name = sa.Column(sa.String(80), nullable=False)
     description = sa.Column(sa.Text())
     organization_id = sa.Column(sa.String(36),
@@ -256,7 +255,7 @@ class ProductVersion(BASE, RefStackBase):
     )
 
     id = sa.Column(sa.String(36), primary_key=True,
-                   default=lambda: six.text_type(uuid.uuid4()))
+                   default=lambda: str(uuid.uuid4()))
     product_id = sa.Column(sa.String(36), sa.ForeignKey('product.id'),
                            index=True, nullable=False, unique=False)
     version = sa.Column(sa.String(length=36), nullable=True)
diff --git a/refstack/tests/api/test_results.py b/refstack/tests/api/test_results.py
index 73b29d8d..27ebc9ec 100644
--- a/refstack/tests/api/test_results.py
+++ b/refstack/tests/api/test_results.py
@@ -17,7 +17,6 @@ import uuid
 
 import mock
 from oslo_config import fixture as config_fixture
-import six
 import webtest.app
 
 from refstack.api import constants as api_const
@@ -207,7 +206,7 @@ class TestResultsEndpoint(api.FunctionalTest):
         """Test get request with nonexistent uuid."""
         self.assertRaises(webtest.app.AppError,
                           self.get_json,
-                          self.URL + six.text_type(uuid.uuid4()))
+                          self.URL + str(uuid.uuid4()))
 
     def test_get_one_schema(self):
         """Test get request for getting JSON schema."""
@@ -230,7 +229,7 @@ class TestResultsEndpoint(api.FunctionalTest):
         responses = []
         for i in range(3):
             fake_results = {
-                'cpid': six.text_type(i),
+                'cpid': str(i),
                 'duration_seconds': i,
                 'results': [
                     {'name': 'tempest.foo.bar'},
diff --git a/refstack/tests/unit/test_api.py b/refstack/tests/unit/test_api.py
index 8ce343fa..b2f14fba 100644
--- a/refstack/tests/unit/test_api.py
+++ b/refstack/tests/unit/test_api.py
@@ -19,7 +19,7 @@ import json
 
 import mock
 from oslo_config import fixture as config_fixture
-from six.moves.urllib import parse
+from urllib import parse
 import webob.exc
 
 from refstack.api import constants as const
diff --git a/refstack/tests/unit/test_api_utils.py b/refstack/tests/unit/test_api_utils.py
index 25c54f61..72f0ff63 100644
--- a/refstack/tests/unit/test_api_utils.py
+++ b/refstack/tests/unit/test_api_utils.py
@@ -22,7 +22,7 @@ from oslo_utils import timeutils
 from oslotest import base
 from pecan import rest
 import jwt
-from six.moves.urllib import parse
+from urllib import parse
 from webob import exc
 
 from refstack.api import constants as const
diff --git a/refstack/tests/unit/test_db.py b/refstack/tests/unit/test_db.py
index 1dbab28c..4ea9eb77 100644
--- a/refstack/tests/unit/test_db.py
+++ b/refstack/tests/unit/test_db.py
@@ -17,7 +17,6 @@
 
 import base64
 import hashlib
-import six
 import mock
 from oslo_config import fixture as config_fixture
 from oslotest import base
@@ -191,7 +190,7 @@ class DBBackendTestCase(base.BaseTestCase):
         test.save.assert_called_once_with(session)
         session.begin.assert_called_once_with()
 
-        self.assertEqual(test_id, six.text_type(_id))
+        self.assertEqual(test_id, str(_id))
         self.assertEqual(test.cpid, fake_tests_result['cpid'])
         self.assertEqual(test.duration_seconds,
                          fake_tests_result['duration_seconds'])
@@ -362,8 +361,8 @@ class DBBackendTestCase(base.BaseTestCase):
     def test_apply_filters_for_query_unsigned(self, mock_meta,
                                               mock_test):
         query = mock.Mock()
-        mock_test.created_at = six.text_type()
-        mock_meta.test_id = six.text_type()
+        mock_test.created_at = str()
+        mock_meta.test_id = str()
 
         filters = {
             api_const.START_DATE: 'fake1',
@@ -413,8 +412,8 @@ class DBBackendTestCase(base.BaseTestCase):
     def test_apply_filters_for_query_signed(self, mock_meta,
                                             mock_test):
         query = mock.Mock()
-        mock_test.created_at = six.text_type()
-        mock_meta.test_id = six.text_type()
+        mock_test.created_at = str()
+        mock_meta.test_id = str()
         mock_meta.meta_key = 'user'
         mock_meta.value = 'test-openid'
 
diff --git a/setup.cfg b/setup.cfg
index 95c9951a..a94a1500 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://refstack.openstack.org
+python_requires = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Developers
@@ -15,6 +16,10 @@ classifier =
     Programming Language :: Python
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3 :: Only
+    Programming Language :: Python :: Implementation :: CPython
 
 [files]
 packages =
diff --git a/tox.ini b/tox.ini
index 7403ca7f..57be49a2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py36,pep8,pip-check-reqs
+envlist = py36,py38,pep8,pip-check-reqs
 minversion = 3.18
 skipsdist = True