diff --git a/src/webassets/bundle.py b/src/webassets/bundle.py
index 547cf4c3..bbd84d44 100644
--- a/src/webassets/bundle.py
+++ b/src/webassets/bundle.py
@@ -1,7 +1,6 @@
 from contextlib import contextmanager
 import os
 from os import path
-from webassets import six
 
 from .filter import get_filter
 from .merge import (FileHunk, UrlHunk, FilterTool, merge, merge_filters,
diff --git a/src/webassets/cache.py b/src/webassets/cache.py
index 60fabb59..53533dea 100644
--- a/src/webassets/cache.py
+++ b/src/webassets/cache.py
@@ -18,7 +18,6 @@
 import errno
 import tempfile
 import warnings
-from webassets import six
 from webassets.merge import BaseHunk
 from webassets.filter import Filter, freezedicts
 from webassets.utils import md5_constructor, pickle
@@ -67,9 +66,9 @@ def walk(obj):
             yield obj.data().encode('utf-8')
         elif isinstance(obj, int):
             yield str(obj).encode('utf-8')
-        elif isinstance(obj, six.text_type):
+        elif isinstance(obj, str):
             yield obj.encode('utf-8')
-        elif isinstance(obj, six.binary_type):
+        elif isinstance(obj, bytes):
             yield obj
         elif hasattr(obj, "id"):
             for i in walk(obj.id()):
diff --git a/src/webassets/filter/compass.py b/src/webassets/filter/compass.py
index 256544fb..84c33cd5 100644
--- a/src/webassets/filter/compass.py
+++ b/src/webassets/filter/compass.py
@@ -32,7 +32,6 @@
 import shutil
 import subprocess
 from io import open
-from webassets import six
 
 from webassets.exceptions import FilterError
 from webassets.filter import Filter, option
@@ -49,13 +48,13 @@ def string_rep(val):
             """ Determine the correct string rep for the config file """
             if isinstance(val, bool):
                 # True -> true and False -> false
-                return six.text_type(val).lower()
-            elif isinstance(val, six.string_types) and val.startswith(':'):
+                return str(val).lower()
+            elif isinstance(val, str) and val.startswith(':'):
                 # ruby symbols, like :nested, used for "output_style"
-                return six.text_type(val)
+                return str(val)
             elif isinstance(val, dict):
                 # ruby hashes, for "sass_options" for example
-                return u'{%s}' % ', '.join("'%s' => '%s'" % i for i in val.items())
+                return '{%s}' % ', '.join("'%s' => '%s'" % i for i in val.items())
             elif isinstance(val, tuple):
                 val = list(val)
             # works fine with strings and lists
diff --git a/src/webassets/filter/spritemapper.py b/src/webassets/filter/spritemapper.py
index 6b30c062..236df009 100644
--- a/src/webassets/filter/spritemapper.py
+++ b/src/webassets/filter/spritemapper.py
@@ -1,5 +1,5 @@
-from webassets.six import StringIO
 from contextlib import contextmanager
+from io import StringIO
 from webassets.filter import Filter
 
 try:
diff --git a/src/webassets/loaders.py b/src/webassets/loaders.py
index 500ab571..20f51571 100644
--- a/src/webassets/loaders.py
+++ b/src/webassets/loaders.py
@@ -9,13 +9,11 @@
 import glob, fnmatch
 import inspect
 import types
-from webassets import six
 try:
     import yaml
 except ImportError:
     pass
 
-from webassets import six
 from webassets import Environment
 from webassets.bundle import Bundle
 from webassets.exceptions import EnvironmentError
@@ -53,7 +51,7 @@ def _yield_bundle_contents(self, data):
         Each item yielded will be either a string representing a file path
         or a bundle."""
         contents = data.get('contents', [])
-        if isinstance(contents, six.string_types):
+        if isinstance(contents, str):
             contents = contents,
         for content in contents:
             if isinstance(content, dict):
@@ -74,7 +72,7 @@ def _get_bundle(self, data):
     def _get_bundles(self, obj, known_bundles=None):
         """Return a dict that keys bundle names to bundles."""
         bundles = {}
-        for key, data in six.iteritems(obj):
+        for key, data in obj.items():
             if data is None:
                 data = {}
             bundles[key] = self._get_bundle(data)
@@ -100,7 +98,7 @@ def _open(self):
 
         The filename can be False if it is unknown.
         """
-        if isinstance(self.file_or_filename, six.string_types):
+        if isinstance(self.file_or_filename, str):
             return open(self.file_or_filename), self.file_or_filename
 
         file = self.file_or_filename
@@ -244,7 +242,7 @@ def load_environment(self):
 
             # Load bundles
             bundles = self._get_bundles(obj.get('bundles', {}))
-            for name, bundle in six.iteritems(bundles):
+            for name, bundle in bundles.items():
                 env.register(name, bundle)
 
             return env
diff --git a/src/webassets/merge.py b/src/webassets/merge.py
index 3bbe28d8..27f69bb1 100644
--- a/src/webassets/merge.py
+++ b/src/webassets/merge.py
@@ -2,16 +2,10 @@
 """
 import contextlib
 
-try:
-    from urllib.request import Request as URLRequest, urlopen
-    from urllib.error import HTTPError
-except ImportError:
-    from urllib2 import Request as URLRequest, urlopen
-    from urllib2 import HTTPError
 import logging
 from io import open
-from webassets import six
-from webassets.six.moves import filter
+from urllib.request import Request as URLRequest, urlopen
+from urllib.error import HTTPError
 
 from .utils import cmp_debug_levels, StringIO, hash_func
 
@@ -120,7 +114,7 @@ def data(self):
             else:
                 with contextlib.closing(response):
                     data = response.read()
-                if isinstance(data, six.binary_type):
+                if isinstance(data, bytes):
                     data = data.decode('utf-8')
                 self._data = data
 
diff --git a/src/webassets/script.py b/src/webassets/script.py
index 65b56d78..e47c3d31 100644
--- a/src/webassets/script.py
+++ b/src/webassets/script.py
@@ -2,6 +2,7 @@
 import os, sys
 import time
 import logging
+from io import StringIO
 
 from webassets.loaders import PythonLoader, YAMLLoader
 from webassets.bundle import get_all_bundle_files
@@ -10,7 +11,6 @@
 from webassets.merge import MemoryHunk
 from webassets.version import get_manifest
 from webassets.cache import FilesystemCache
-from webassets.utils import set, StringIO
 
 
 __all__ = ('CommandError', 'CommandLineEnvironment', 'main')
diff --git a/src/webassets/utils.py b/src/webassets/utils.py
index 985f5cec..fc9232c1 100644
--- a/src/webassets/utils.py
+++ b/src/webassets/utils.py
@@ -1,9 +1,13 @@
-from webassets import six
+import base64
 import contextlib
+import hashlib
 import os
+import pickle
 import sys
 import re
+from io import StringIO
 from itertools import takewhile
+from urllib import parse as urlparse
 
 from .exceptions import BundleError
 
@@ -11,47 +15,8 @@
 __all__ = ('md5_constructor', 'pickle', 'set', 'StringIO',
            'common_path_prefix', 'working_directory', 'is_url')
 
-
-import base64
-
-if sys.version_info >= (2, 5):
-    import hashlib
-    md5_constructor = hashlib.md5
-else:
-    import md5
-    md5_constructor = md5.new
-
-
-try:
-    import cPickle as pickle
-except ImportError:
-    import pickle
-
-
-try:
-    set
-except NameError:
-    from sets import Set as set
-else:
-    set = set
-
-
-try:
-    FileNotFoundError
-except NameError:
-    FileNotFoundError = IOError
-else:
-    FileNotFoundError = FileNotFoundError
-
-
-from webassets.six import StringIO
-
-
-try:
-    from urllib import parse as urlparse
-except ImportError:     # Python 2
-    import urlparse
-    import urllib
+md5_constructor = hashlib.md5
+set = set
 
 def hash_func(data):
     from .cache import make_md5
@@ -149,7 +114,7 @@ def resolve_option(option, env=None):
             return instantiate(option, env)
 
         # If it is a string
-        elif isinstance(option, six.string_types):
+        elif isinstance(option, str):
             parts = option.split(':', 1)
             key = parts[0]
             arg = parts[1] if len(parts) > 1 else None
diff --git a/src/webassets/version.py b/src/webassets/version.py
index 70d51771..ffc59ee9 100644
--- a/src/webassets/version.py
+++ b/src/webassets/version.py
@@ -4,7 +4,6 @@
 
 import os
 import pickle
-from webassets import six
 
 from webassets.merge import FileHunk
 from webassets.utils import md5_constructor, RegistryMetaclass, is_url
@@ -19,9 +18,9 @@ class VersionIndeterminableError(Exception):
     pass
 
 
-class Version(six.with_metaclass(RegistryMetaclass(
+class Version(metaclass=RegistryMetaclass(
     clazz=lambda: Version, attribute='determine_version',
-    desc='a version implementation'))):
+    desc='a version implementation')):
     """A Version class that can be assigned to the ``Environment.versioner``
     attribute.
 
@@ -165,8 +164,8 @@ def determine_version(self, bundle, ctx, hunk=None):
         return hasher.hexdigest()[:self.length]
 
 
-class Manifest(six.with_metaclass(RegistryMetaclass(
-    clazz=lambda: Manifest, desc='a manifest implementation'))):
+class Manifest(metaclass=RegistryMetaclass(
+    clazz=lambda: Manifest, desc='a manifest implementation')):
     """Persists information about the versions bundles are at.
 
     The Manifest plays a role only if you insert the bundle version in your
diff --git a/tests/test_bundle_build.py b/tests/test_bundle_build.py
index 4f2e5536..c801b9bd 100644
--- a/tests/test_bundle_build.py
+++ b/tests/test_bundle_build.py
@@ -147,7 +147,7 @@ def test_auto_create_target_directory(self):
 
     def test_with_custom_output(self):
         """build() method can write to a custom file object."""
-        from webassets.six import StringIO
+        from io import StringIO
         buffer = StringIO()
         self.mkbundle('in1', 'in2', output='out').build(output=buffer)
         assert buffer.getvalue() == 'A\nB'
diff --git a/tests/test_bundle_various.py b/tests/test_bundle_various.py
index cb2ec1b2..10c07e15 100644
--- a/tests/test_bundle_various.py
+++ b/tests/test_bundle_various.py
@@ -4,21 +4,15 @@
 """
 
 import copy
+from io import StringIO
 from os import path
 import uuid
-try:
-    from urllib.request import \
-        HTTPHandler, build_opener, install_opener, addinfourl
-except ImportError: # Py2
-    from urllib2 import HTTPHandler, build_opener, install_opener, addinfourl
+from urllib.request import \
+     HTTPHandler, build_opener, install_opener, addinfourl
 
 import pytest
 
-from webassets.six import StringIO
-from webassets.six.moves import filter
-
 from webassets import Bundle
-from webassets.utils import set
 from webassets.bundle import get_all_bundle_files
 from webassets.env import Environment
 from webassets.exceptions import BundleError, BuildError
diff --git a/tests/test_environment.py b/tests/test_environment.py
index 453ce04f..3859d68b 100644
--- a/tests/test_environment.py
+++ b/tests/test_environment.py
@@ -2,7 +2,6 @@
 
 import pytest
 
-from webassets import six
 from webassets import Environment
 from webassets.env import RegisterError
 from webassets import Bundle
@@ -222,7 +221,7 @@ def test_versioner(self):
 
         # Standard string values
         self.m.versions = 'timestamp'
-        assert isinstance(self.m.config['versions'], six.string_types)
+        assert isinstance(self.m.config['versions'], str)
         assert isinstance(self.m.versions, Version)
         assert self.m.versions == 'timestamp'   # __eq__
         assert self.m.versions != 'hash'
diff --git a/tests/test_filters.py b/tests/test_filters.py
index b128fc44..8b97370f 100644
--- a/tests/test_filters.py
+++ b/tests/test_filters.py
@@ -1185,11 +1185,7 @@ def test_compass_with_unicode(self):
 
         # It's very hard to test this with doctest_match
         # And by asserting that it's in the content this test is proven
-        from webassets.six import PY3
-        if PY3:
-            assert """content: "áé";""" in self.get('out.css')
-        else:
-            assert """content: "\xc3\xa1\xc3\xa9";""" in self.get('out.css')
+        assert """content: "áé";""" in self.get('out.css')
 
     def test_images_dir(self):
         # [bug] Make sure the compass plugin can reference images. It expects
@@ -1229,8 +1225,7 @@ def setup_method(self):
         self.compass_config = CompassConfig(self.config).to_string()
 
     def test_compass_config_is_unicode(self):
-        from webassets.six import text_type
-        assert isinstance(self.compass_config, text_type)
+        assert isinstance(self.compass_config, str)
 
     def test_string_value(self):
         assert "http_path = '/'" in self.compass_config