diff --git a/mitmproxy/builtins/serverplayback.py b/mitmproxy/builtins/serverplayback.py
index 29fc95efc..b495bc27e 100644
--- a/mitmproxy/builtins/serverplayback.py
+++ b/mitmproxy/builtins/serverplayback.py
@@ -1,5 +1,5 @@
 from __future__ import absolute_import, print_function, division
-from six.moves import urllib
+import urllib
 import hashlib
 
 from netlib import strutils
diff --git a/mitmproxy/builtins/stickycookie.py b/mitmproxy/builtins/stickycookie.py
index 027e624fa..d89bd92d1 100644
--- a/mitmproxy/builtins/stickycookie.py
+++ b/mitmproxy/builtins/stickycookie.py
@@ -1,5 +1,6 @@
 import collections
-from six.moves import http_cookiejar
+from http import cookiejar
+
 from netlib.http import cookies
 
 from mitmproxy import exceptions
@@ -20,9 +21,9 @@ def ckey(attrs, f):
 
 
 def domain_match(a, b):
-    if http_cookiejar.domain_match(a, b):
+    if cookiejar.domain_match(a, b):
         return True
-    elif http_cookiejar.domain_match(a, b.strip(".")):
+    elif cookiejar.domain_match(a, b.strip(".")):
         return True
     return False
 
diff --git a/mitmproxy/console/grideditor/base.py b/mitmproxy/console/grideditor/base.py
index 8b80badbf..eed70c0b0 100644
--- a/mitmproxy/console/grideditor/base.py
+++ b/mitmproxy/console/grideditor/base.py
@@ -2,7 +2,6 @@ from __future__ import absolute_import, print_function, division
 import abc
 import copy
 
-import six
 import urwid
 from mitmproxy.console import common
 from mitmproxy.console import signals
@@ -24,8 +23,7 @@ FOOTER_EDITING = [
 ]
 
 
-@six.add_metaclass(abc.ABCMeta)
-class Column(object):
+class Column(object, metaclass=abc.ABCMeta):
     subeditor = None
 
     def __init__(self, heading):
diff --git a/mitmproxy/console/master.py b/mitmproxy/console/master.py
index 16abcb96a..d648d808c 100644
--- a/mitmproxy/console/master.py
+++ b/mitmproxy/console/master.py
@@ -13,7 +13,6 @@ import tempfile
 import traceback
 import weakref
 
-import six
 import urwid
 from typing import Optional  # noqa
 
@@ -357,13 +356,8 @@ class ConsoleMaster(flow.FlowMaster):
     def spawn_editor(self, data):
         text = not isinstance(data, bytes)
         fd, name = tempfile.mkstemp('', "mproxy", text=text)
-        if six.PY2:
-            os.close(fd)
-            with open(name, "w" if text else "wb") as f:
-                f.write(data)
-        else:
-            with open(fd, "w" if text else "wb") as f:
-                f.write(data)
+        with open(fd, "w" if text else "wb") as f:
+            f.write(data)
         # if no EDITOR is set, assume 'vi'
         c = os.environ.get("EDITOR") or "vi"
         cmd = shlex.split(c)
diff --git a/mitmproxy/contentviews.py b/mitmproxy/contentviews.py
index 83e6a7ad0..03ef8f052 100644
--- a/mitmproxy/contentviews.py
+++ b/mitmproxy/contentviews.py
@@ -16,24 +16,26 @@ from __future__ import absolute_import, print_function, division
 
 import cssutils
 import datetime
-import html2text
-import jsbeautifier
 import json
 import logging
-import lxml.etree
-import lxml.html
 import subprocess
 import traceback
+import io
+from typing import Mapping  # noqa
+
+import lxml.etree
+import lxml.html
 from PIL import ExifTags
 from PIL import Image
+import html2text
+import jsbeautifier
+
 from mitmproxy import exceptions
 from mitmproxy.contrib.wbxml import ASCommandResponse
 from netlib import http
 from netlib import multidict
 from netlib import strutils
 from netlib.http import url
-from six import BytesIO
-from typing import Mapping  # noqa
 
 try:
     import pyamf
@@ -422,7 +424,7 @@ class ViewImage(View):
 
     def __call__(self, data, **metadata):
         try:
-            img = Image.open(BytesIO(data))
+            img = Image.open(io.BytesIO(data))
         except IOError:
             return None
         parts = [
diff --git a/mitmproxy/contrib/tls/utils.py b/mitmproxy/contrib/tls/utils.py
index 4c917303e..87afbacb7 100644
--- a/mitmproxy/contrib/tls/utils.py
+++ b/mitmproxy/contrib/tls/utils.py
@@ -6,15 +6,12 @@ from __future__ import absolute_import, division, print_function
 
 import construct
 
-import six
-
-
 class _UBInt24(construct.Adapter):
     def _encode(self, obj, context):
-        return (
-            six.int2byte((obj & 0xFF0000) >> 16) +
-            six.int2byte((obj & 0x00FF00) >> 8) +
-            six.int2byte(obj & 0x0000FF)
+        return bytes(
+            (obj & 0xFF0000) >> 16,
+            (obj & 0x00FF00) >> 8,
+            obj & 0x0000FF
         )
 
     def _decode(self, obj, context):
diff --git a/mitmproxy/contrib/tnetstring.py b/mitmproxy/contrib/tnetstring.py
index f5e1d5c10..22ecab652 100644
--- a/mitmproxy/contrib/tnetstring.py
+++ b/mitmproxy/contrib/tnetstring.py
@@ -41,7 +41,6 @@ all other strings are returned as plain bytes.
 """
 
 import collections
-import six
 from typing import io, Union, Tuple  # noqa
 
 TSerializable = Union[None, bool, int, float, bytes, list, tuple, dict]
@@ -96,7 +95,7 @@ def _rdumpq(q, size, value):
     elif value is False:
         write(b'5:false!')
         return size + 8
-    elif isinstance(value, six.integer_types):
+    elif isinstance(value, int):
         data = str(value).encode()
         ldata = len(data)
         span = str(ldata).encode()
@@ -191,16 +190,12 @@ def load(file_handle):
 
 def parse(data_type, data):
     # type: (int, bytes) -> TSerializable
-    if six.PY2:
-        data_type = ord(data_type)
     if data_type == ord(b','):
         return data
     if data_type == ord(b';'):
         return data.decode("utf8")
     if data_type == ord(b'#'):
         try:
-            if six.PY2:
-                return long(data)
             return int(data)
         except ValueError:
             raise ValueError("not a tnetstring: invalid integer literal: {}".format(data))
diff --git a/mitmproxy/contrib/wbxml/ASWBXMLByteQueue.py b/mitmproxy/contrib/wbxml/ASWBXMLByteQueue.py
index ecc76efb5..b616028c4 100644
--- a/mitmproxy/contrib/wbxml/ASWBXMLByteQueue.py
+++ b/mitmproxy/contrib/wbxml/ASWBXMLByteQueue.py
@@ -5,7 +5,7 @@
 Inspired by EAS Inspector for Fiddler
 https://easinspectorforfiddler.codeplex.com
 
------ The MIT License (MIT) ----- 
+----- The MIT License (MIT) -----
 Filename: ASWBXMLByteQueue.py
 Copyright (c) 2014, David P. Shaw
 
@@ -27,25 +27,25 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 '''
-from six.moves.queue import Queue
+from queue import Queue
 import logging
 
 class ASWBXMLByteQueue(Queue):
 
     def __init__(self, wbxmlBytes):
-        
+
         self.bytesDequeued = 0
         self.bytesEnqueued = 0
-        
+
         Queue.__init__(self)
 
         for byte in wbxmlBytes:
             self.put(ord(byte))
             self.bytesEnqueued += 1
-        
-        
+
+
         logging.debug("Array byte count: %d, enqueued: %d" % (self.qsize(), self.bytesEnqueued))
-    
+
     """
     Created to debug the dequeueing of bytes
     """
@@ -54,18 +54,18 @@ class ASWBXMLByteQueue(Queue):
         self.bytesDequeued += 1
         logging.debug("Dequeued byte 0x{0:X} ({1} total)".format(singleByte, self.bytesDequeued))
         return singleByte
-    
+
     """
     Return true if the continuation bit is set in the byte
     """
     def checkContinuationBit(self, byteval):
         continuationBitmask = 0x80
         return (continuationBitmask & byteval) != 0
-    
+
     def dequeueMultibyteInt(self):
         iReturn = 0
         singleByte = 0xFF
-         
+
         while True:
             iReturn <<= 7
             if (self.qsize() == 0):
@@ -100,4 +100,3 @@ class ASWBXMLByteQueue(Queue):
                     break
 
         return strReturn
-
diff --git a/mitmproxy/controller.py b/mitmproxy/controller.py
index 4fd66bfab..579cf92dc 100644
--- a/mitmproxy/controller.py
+++ b/mitmproxy/controller.py
@@ -3,8 +3,7 @@ from __future__ import absolute_import, print_function, division
 import functools
 import threading
 import contextlib
-
-from six.moves import queue
+import queue
 
 from mitmproxy import addons
 from mitmproxy import options
diff --git a/mitmproxy/flow/export.py b/mitmproxy/flow/export.py
index eb2d38d28..44ba1905d 100644
--- a/mitmproxy/flow/export.py
+++ b/mitmproxy/flow/export.py
@@ -2,21 +2,15 @@ from __future__ import absolute_import, print_function, division
 
 import json
 import re
-from textwrap import dedent
-
-import six
-from six.moves import urllib
+import textwrap
+import urllib
 
 import netlib.http
 
 
 def _native(s):
-    if six.PY2:
-        if isinstance(s, str):
-            return s.encode()
-    else:
-        if isinstance(s, bytes):
-            return s.decode()
+    if isinstance(s, bytes):
+        return s.decode()
     return s
 
 
@@ -49,7 +43,7 @@ def curl_command(flow):
 
 
 def python_code(flow):
-    code = dedent("""
+    code = textwrap.dedent("""
         import requests
 
         url = '{url}'
@@ -110,7 +104,7 @@ def is_json(headers, content):
 
 
 def locust_code(flow):
-    code = dedent("""
+    code = textwrap.dedent("""
         from locust import HttpLocust, TaskSet, task
 
         class UserBehavior(TaskSet):
diff --git a/mitmproxy/flow/io_compat.py b/mitmproxy/flow/io_compat.py
index b01f96b66..e7753adb0 100644
--- a/mitmproxy/flow/io_compat.py
+++ b/mitmproxy/flow/io_compat.py
@@ -3,7 +3,6 @@ This module handles the import of mitmproxy flows generated by old versions.
 """
 from __future__ import absolute_import, print_function, division
 
-import six
 from typing import Any  # noqa
 
 from netlib import version, strutils
@@ -93,23 +92,21 @@ def _convert_dict_vals(o, values_to_convert):
 def convert_unicode(data):
     # type: (dict) -> dict
     """
-    The Python 2 version of mitmproxy serializes everything as bytes.
     This method converts between Python 3 and Python 2 dumpfiles.
     """
-    if not six.PY2:
-        data = _convert_dict_keys(data)
-        data = _convert_dict_vals(
-            data, {
-                "type": True,
-                "id": True,
-                "request": {
-                    "first_line_format": True
-                },
-                "error": {
-                    "msg": True
-                }
+    data = _convert_dict_keys(data)
+    data = _convert_dict_vals(
+        data, {
+            "type": True,
+            "id": True,
+            "request": {
+                "first_line_format": True
+            },
+            "error": {
+                "msg": True
             }
-        )
+        }
+    )
     return data
 
 
diff --git a/mitmproxy/flow/state.py b/mitmproxy/flow/state.py
index 26b18c84d..f6395c79d 100644
--- a/mitmproxy/flow/state.py
+++ b/mitmproxy/flow/state.py
@@ -2,15 +2,13 @@ from __future__ import absolute_import, print_function, division
 
 from abc import abstractmethod, ABCMeta
 
-import six
 from typing import List  # noqa
 
 from mitmproxy import flowfilter
 from mitmproxy import models  # noqa
 
 
-@six.add_metaclass(ABCMeta)
-class FlowList(object):
+class FlowList(metaclass=ABCMeta):
     def __init__(self):
         self._list = []  # type: List[models.Flow]
 
@@ -26,9 +24,6 @@ class FlowList(object):
     def __bool__(self):
         return bool(self._list)
 
-    if six.PY2:
-        __nonzero__ = __bool__
-
     def __len__(self):
         return len(self._list)
 
diff --git a/mitmproxy/main.py b/mitmproxy/main.py
index 6ae99bddd..e39742f34 100644
--- a/mitmproxy/main.py
+++ b/mitmproxy/main.py
@@ -4,8 +4,6 @@ import os
 import signal
 import sys
 
-from six.moves import _thread  # PY3: We only need _thread.error, which is an alias of RuntimeError in 3.3+
-
 from mitmproxy import cmdline
 from mitmproxy import exceptions
 from mitmproxy.proxy import config
@@ -78,7 +76,7 @@ def mitmproxy(args=None):  # pragma: no cover
         sys.exit(1)
     try:
         m.run()
-    except (KeyboardInterrupt, _thread.error):
+    except (KeyboardInterrupt, RuntimeError):
         pass
 
 
@@ -109,7 +107,7 @@ def mitmdump(args=None):  # pragma: no cover
     except (dump.DumpError, exceptions.OptionsError) as e:
         print("mitmdump: %s" % e, file=sys.stderr)
         sys.exit(1)
-    except (KeyboardInterrupt, _thread.error):
+    except (KeyboardInterrupt, RuntimeError):
         pass
     if master is None or master.has_errored:
         print("mitmdump: errors occurred during run", file=sys.stderr)
@@ -142,5 +140,5 @@ def mitmweb(args=None):  # pragma: no cover
         sys.exit(1)
     try:
         m.run()
-    except (KeyboardInterrupt, _thread.error):
+    except (KeyboardInterrupt, RuntimeError):
         pass
diff --git a/mitmproxy/models/connections.py b/mitmproxy/models/connections.py
index 9778b7f12..a99327d87 100644
--- a/mitmproxy/models/connections.py
+++ b/mitmproxy/models/connections.py
@@ -4,8 +4,6 @@ import time
 import copy
 import os
 
-import six
-
 from mitmproxy import stateobject
 from netlib import certutils
 from netlib import tcp
@@ -47,9 +45,6 @@ class ClientConnection(tcp.BaseHandler, stateobject.StateObject):
     def __bool__(self):
         return bool(self.connection) and not self.finished
 
-    if six.PY2:
-        __nonzero__ = __bool__
-
     def __repr__(self):
         return "<ClientConnection: {ssl}{address}>".format(
             ssl="[ssl] " if self.ssl_established else "",
@@ -136,9 +131,6 @@ class ServerConnection(tcp.TCPClient, stateobject.StateObject):
     def __bool__(self):
         return bool(self.connection) and not self.finished
 
-    if six.PY2:
-        __nonzero__ = __bool__
-
     def __repr__(self):
         if self.ssl_established and self.sni:
             ssl = "[ssl: {0}] ".format(self.sni)
diff --git a/mitmproxy/platform/windows.py b/mitmproxy/platform/windows.py
index 576516e22..54d29c72d 100644
--- a/mitmproxy/platform/windows.py
+++ b/mitmproxy/platform/windows.py
@@ -10,8 +10,8 @@ import time
 import configargparse
 from pydivert import enum
 from pydivert import windivert
-from six.moves import cPickle as pickle
-from six.moves import socketserver
+import pickle
+import socketserver
 
 PROXY_API_PORT = 8085
 
diff --git a/mitmproxy/protocol/base.py b/mitmproxy/protocol/base.py
index da6e83563..b280ec35a 100644
--- a/mitmproxy/protocol/base.py
+++ b/mitmproxy/protocol/base.py
@@ -1,9 +1,5 @@
 from __future__ import absolute_import, print_function, division
 
-import sys
-
-import six
-
 import netlib.exceptions
 from mitmproxy import exceptions
 from mitmproxy import models
@@ -184,12 +180,8 @@ class ServerConnectionMixin(object):
         try:
             self.server_conn.connect()
         except netlib.exceptions.TcpException as e:
-            six.reraise(
-                exceptions.ProtocolException,
-                exceptions.ProtocolException(
-                    "Server connection to {} failed: {}".format(
-                        repr(self.server_conn.address), str(e)
-                    )
-                ),
-                sys.exc_info()[2]
+            raise exceptions.ProtocolException(
+                "Server connection to {} failed: {}".format(
+                    repr(self.server_conn.address), str(e)
+                )
             )
diff --git a/mitmproxy/protocol/http.py b/mitmproxy/protocol/http.py
index 35b375de6..54b611993 100644
--- a/mitmproxy/protocol/http.py
+++ b/mitmproxy/protocol/http.py
@@ -2,8 +2,6 @@ from __future__ import absolute_import, print_function, division
 
 import h2.exceptions
 import netlib.exceptions
-import six
-import sys
 import time
 import traceback
 from mitmproxy import exceptions
@@ -83,9 +81,6 @@ class ConnectServerConnection(object):
     def __bool__(self):
         return bool(self.via)
 
-    if six.PY2:
-        __nonzero__ = __bool__
-
 
 class UpstreamConnectLayer(base.Layer):
 
@@ -159,12 +154,8 @@ class HttpLayer(base.Layer):
                 # We optimistically guess there might be an HTTP client on the
                 # other end
                 self.send_error_response(400, repr(e))
-                six.reraise(
-                    exceptions.ProtocolException,
-                    exceptions.ProtocolException(
-                        "HTTP protocol error in client request: {}".format(e)
-                    ),
-                    sys.exc_info()[2]
+                raise exceptions.ProtocolException(
+                    "HTTP protocol error in client request: {}".format(e)
                 )
 
             self.log("request", "debug", [repr(request)])
@@ -193,10 +184,7 @@ class HttpLayer(base.Layer):
 
             # update host header in reverse proxy mode
             if self.config.options.mode == "reverse":
-                if six.PY2:
-                    flow.request.headers["Host"] = self.config.upstream_server.address.host.encode()
-                else:
-                    flow.request.headers["Host"] = self.config.upstream_server.address.host
+                flow.request.headers["Host"] = self.config.upstream_server.address.host
 
             # set upstream auth
             if self.mode == "upstream" and self.config.upstream_auth is not None:
@@ -244,8 +232,9 @@ class HttpLayer(base.Layer):
                     self.channel.ask("error", flow)
                     return
                 else:
-                    six.reraise(exceptions.ProtocolException, exceptions.ProtocolException(
-                        "Error in HTTP connection: %s" % repr(e)), sys.exc_info()[2])
+                    raise exceptions.ProtocolException(
+                        "Error in HTTP connection: %s" % repr(e)
+                    )
             finally:
                 if flow:
                     flow.live = False
diff --git a/mitmproxy/protocol/http2.py b/mitmproxy/protocol/http2.py
index ae12406fc..ffc556843 100644
--- a/mitmproxy/protocol/http2.py
+++ b/mitmproxy/protocol/http2.py
@@ -6,10 +6,9 @@ import traceback
 import functools
 
 import h2.exceptions
-import six
 from h2 import connection
 from h2 import events
-from six.moves import queue
+import queue
 
 import netlib.exceptions
 from mitmproxy import exceptions
@@ -208,7 +207,7 @@ class Http2Layer(base.Layer):
         return True
 
     def _handle_remote_settings_changed(self, event, other_conn):
-        new_settings = dict([(key, cs.new_value) for (key, cs) in six.iteritems(event.changed_settings)])
+        new_settings = dict([(key, cs.new_value) for (key, cs) in event.changed_settings.items()])
         other_conn.h2.safe_update_settings(new_settings)
         return True
 
diff --git a/mitmproxy/protocol/tls.py b/mitmproxy/protocol/tls.py
index 4792edb86..537737172 100644
--- a/mitmproxy/protocol/tls.py
+++ b/mitmproxy/protocol/tls.py
@@ -1,10 +1,8 @@
 from __future__ import absolute_import, print_function, division
 
 import struct
-import sys
 
 import construct
-import six
 
 import netlib.exceptions
 from mitmproxy import exceptions
@@ -214,20 +212,12 @@ def is_tls_record_magic(d):
 
     # TLS ClientHello magic, works for SSLv3, TLSv1.0, TLSv1.1, TLSv1.2
     # http://www.moserware.com/2009/06/first-few-milliseconds-of-https.html#client-hello
-    if six.PY2:
-        return (
-            len(d) == 3 and
-            d[0] == '\x16' and
-            d[1] == '\x03' and
-            d[2] in ('\x00', '\x01', '\x02', '\x03')
-        )
-    else:
-        return (
-            len(d) == 3 and
-            d[0] == 0x16 and
-            d[1] == 0x03 and
-            0x0 <= d[2] <= 0x03
-        )
+    return (
+        len(d) == 3 and
+        d[0] == 0x16 and
+        d[1] == 0x03 and
+        0x0 <= d[2] <= 0x03
+    )
 
 
 def get_client_hello(client_conn):
@@ -467,7 +457,7 @@ class TlsLayer(base.Layer):
                 self._establish_tls_with_client()
             except:
                 pass
-            six.reraise(*sys.exc_info())
+            raise
 
         self._establish_tls_with_client()
 
@@ -497,15 +487,11 @@ class TlsLayer(base.Layer):
             # raises ann error.
             self.client_conn.rfile.peek(1)
         except netlib.exceptions.TlsException as e:
-            six.reraise(
-                exceptions.ClientHandshakeException,
-                exceptions.ClientHandshakeException(
-                    "Cannot establish TLS with client (sni: {sni}): {e}".format(
-                        sni=self._client_hello.sni, e=repr(e)
-                    ),
-                    self._client_hello.sni or repr(self.server_conn.address)
+            raise exceptions.ClientHandshakeException(
+                "Cannot establish TLS with client (sni: {sni}): {e}".format(
+                    sni=self._client_hello.sni, e=repr(e)
                 ),
-                sys.exc_info()[2]
+                self._client_hello.sni or repr(self.server_conn.address)
             )
 
     def _establish_tls_with_server(self):
@@ -545,21 +531,14 @@ class TlsLayer(base.Layer):
                 self.log(str(tls_cert_err), "warn")
                 self.log("Ignoring server verification error, continuing with connection", "warn")
         except netlib.exceptions.InvalidCertificateException as e:
-            six.reraise(
-                exceptions.InvalidServerCertificate,
-                exceptions.InvalidServerCertificate(str(e)),
-                sys.exc_info()[2]
-            )
+            raise exceptions.InvalidServerCertificate(str(e))
         except netlib.exceptions.TlsException as e:
-            six.reraise(
-                exceptions.TlsProtocolException,
-                exceptions.TlsProtocolException("Cannot establish TLS with {address} (sni: {sni}): {e}".format(
-                    address=repr(self.server_conn.address),
-                    sni=self.server_sni,
-                    e=repr(e),
-                )),
-                sys.exc_info()[2]
-            )
+            raise exceptions.TlsProtocolException(
+                "Cannot establish TLS with {address} (sni: {sni}): {e}".format(
+                address=repr(self.server_conn.address),
+                sni=self.server_sni,
+                e=repr(e),
+            ))
 
         proto = self.alpn_for_client_connection.decode() if self.alpn_for_client_connection else '-'
         self.log("ALPN selected by server: {}".format(proto), "debug")
diff --git a/mitmproxy/proxy/config.py b/mitmproxy/proxy/config.py
index df4dd4c8f..e5b3bd048 100644
--- a/mitmproxy/proxy/config.py
+++ b/mitmproxy/proxy/config.py
@@ -6,7 +6,6 @@ import os
 import re
 from netlib import strutils
 
-import six
 from OpenSSL import SSL, crypto
 
 from mitmproxy import exceptions
@@ -38,9 +37,6 @@ class HostMatcher(object):
     def __bool__(self):
         return bool(self.patterns)
 
-    if six.PY2:
-        __nonzero__ = __bool__
-
 
 ServerSpec = collections.namedtuple("ServerSpec", "scheme address")
 
diff --git a/mitmproxy/proxy/root_context.py b/mitmproxy/proxy/root_context.py
index cfa04bdf7..d3f3c6df8 100644
--- a/mitmproxy/proxy/root_context.py
+++ b/mitmproxy/proxy/root_context.py
@@ -1,9 +1,5 @@
 from __future__ import absolute_import, print_function, division
 
-import sys
-
-import six
-
 import netlib.exceptions
 from mitmproxy import controller
 from mitmproxy import exceptions
@@ -50,7 +46,7 @@ class RootContext(object):
         try:
             d = top_layer.client_conn.rfile.peek(3)
         except netlib.exceptions.TcpException as e:
-            six.reraise(exceptions.ProtocolException, exceptions.ProtocolException(str(e)), sys.exc_info()[2])
+            raise exceptions.ProtocolException(str(e))
         client_tls = protocol.is_tls_record_magic(d)
 
         # 1. check for --ignore
@@ -101,7 +97,7 @@ class RootContext(object):
         is_ascii = (
             len(d) == 3 and
             # expect A-Za-z
-            all(65 <= x <= 90 or 97 <= x <= 122 for x in six.iterbytes(d))
+            all(65 <= x <= 90 or 97 <= x <= 122 for x in d)
         )
         if self.config.options.rawtcp and not is_ascii:
             return protocol.RawTCPLayer(top_layer)
diff --git a/mitmproxy/proxy/server.py b/mitmproxy/proxy/server.py
index 182f46024..0fedaa747 100644
--- a/mitmproxy/proxy/server.py
+++ b/mitmproxy/proxy/server.py
@@ -4,8 +4,6 @@ import socket
 import sys
 import traceback
 
-import six
-
 import netlib.exceptions
 from mitmproxy import exceptions
 from mitmproxy import models
@@ -46,10 +44,8 @@ class ProxyServer(tcp.TCPServer):
                 (config.options.listen_host, config.options.listen_port)
             )
         except socket.error as e:
-            six.reraise(
-                exceptions.ServerException,
-                exceptions.ServerException('Error starting proxy server: ' + repr(e)),
-                sys.exc_info()[2]
+            raise exceptions.ServerException(
+                'Error starting proxy server: ' + repr(e)
             )
         self.channel = None
 
diff --git a/mitmproxy/stateobject.py b/mitmproxy/stateobject.py
index 5e4ae6e3d..a38315c14 100644
--- a/mitmproxy/stateobject.py
+++ b/mitmproxy/stateobject.py
@@ -1,6 +1,5 @@
 from __future__ import absolute_import, print_function, division
 
-import six
 from typing import Any
 from typing import List
 
@@ -34,7 +33,7 @@ class StateObject(netlib.basetypes.Serializable):
         Retrieve object state.
         """
         state = {}
-        for attr, cls in six.iteritems(self._stateobject_attributes):
+        for attr, cls in self._stateobject_attributes.items():
             val = getattr(self, attr)
             if val is None:
                 state[attr] = None
@@ -51,7 +50,7 @@ class StateObject(netlib.basetypes.Serializable):
         Load object state from data returned by a get_state call.
         """
         state = state.copy()
-        for attr, cls in six.iteritems(self._stateobject_attributes):
+        for attr, cls in self._stateobject_attributes.items():
             val = state.pop(attr)
             if val is None:
                 setattr(self, attr, val)
diff --git a/mitmproxy/web/app.py b/mitmproxy/web/app.py
index 34969870b..e5a050989 100644
--- a/mitmproxy/web/app.py
+++ b/mitmproxy/web/app.py
@@ -8,7 +8,6 @@ import re
 import hashlib
 
 
-import six
 import tornado.websocket
 import tornado.web
 from io import BytesIO
@@ -242,10 +241,10 @@ class FlowHandler(RequestHandler):
     def put(self, flow_id):
         flow = self.flow
         flow.backup()
-        for a, b in six.iteritems(self.json):
+        for a, b in self.json.items():
             if a == "request":
                 request = flow.request
-                for k, v in six.iteritems(b):
+                for k, v in b.items():
                     if k in ["method", "scheme", "host", "path", "http_version"]:
                         setattr(request, k, str(v))
                     elif k == "port":
@@ -259,7 +258,7 @@ class FlowHandler(RequestHandler):
 
             elif a == "response":
                 response = flow.response
-                for k, v in six.iteritems(b):
+                for k, v in b.items():
                     if k == "msg":
                         response.msg = str(v)
                     elif k == "code":
@@ -387,7 +386,7 @@ class Settings(RequestHandler):
 
     def put(self):
         update = {}
-        for k, v in six.iteritems(self.json):
+        for k, v in self.json.items():
             if k == "intercept":
                 self.master.options.intercept = v
                 update[k] = v