diff --git a/src/foolscap/appserver/cli.py b/src/foolscap/appserver/cli.py
index 719056d..2296650 100644
--- a/src/foolscap/appserver/cli.py
+++ b/src/foolscap/appserver/cli.py
@@ -454,7 +454,7 @@ def run_flappserver(argv=None, run_by_human=True):
         r = dispatch(command, so)
     except (usage.UsageError, BadServiceArguments) as e:
         r = 1
-        print("Error:", six.text_type(e), file=so.stderr)
+        print("Error:", str(e), file=so.stderr)
     from twisted.internet import defer
     if run_by_human:
         if isinstance(r, defer.Deferred):
diff --git a/src/foolscap/banana.py b/src/foolscap/banana.py
index 133b9ac..77b1a81 100644
--- a/src/foolscap/banana.py
+++ b/src/foolscap/banana.py
@@ -11,7 +11,6 @@
 from foolscap.slicers.allslicers import RootSlicer, RootUnslicer
 from foolscap.slicers.allslicers import ReplaceVocabSlicer, AddVocabSlicer
 
-from .util import long_type
 from . import stringchain
 from . import tokens
 from .tokens import SIZE_LIMIT, STRING, LIST, INT, NEG, \
@@ -60,7 +59,7 @@ def bytes_to_long(s):
 
     This is (essentially) the inverse of long_to_bytes().
     """
-    acc = long_type(0)
+    acc = 0
     for i in six.iterbytes(s):
         acc <<= 8
         acc += i
@@ -68,7 +67,7 @@ def bytes_to_long(s):
 
 HIGH_BIT_SET = b"\x80"
 
-SIMPLE_TOKENS = six.integer_types + (float, six.binary_type)
+SIMPLE_TOKENS = (int, float, bytes)
 
 # Banana is a big class. It is split up into three sections: sending,
 # receiving, and connection setup. These used to be separate classes, but
@@ -417,7 +416,7 @@ def outgoingVocabTableWasReplaced(self, newTable):
         # this is called by the ReplaceVocabSlicer to manipulate our table.
         # It must certainly *not* be called by higher-level user code.
         for k in newTable.keys():
-            assert isinstance(k, six.binary_type)
+            assert isinstance(k, bytes)
         self.outgoingVocabulary = newTable
         if newTable:
             maxIndex = max(newTable.values()) + 1
@@ -466,7 +465,7 @@ def sendOpen(self):
 
     def sendToken(self, obj):
         write = self.transport.write
-        if isinstance(obj, six.integer_types):
+        if isinstance(obj, int):
             if obj >= 2**31:
                 s = long_to_bytes(obj)
                 int2b128(len(s), write)
@@ -486,7 +485,7 @@ def sendToken(self, obj):
         elif isinstance(obj, float):
             write(FLOAT)
             write(struct.pack("!d", obj))
-        elif isinstance(obj, six.binary_type):
+        elif isinstance(obj, bytes):
             if obj in self.outgoingVocabulary:
                 symbolID = self.outgoingVocabulary[obj]
                 int2b128(symbolID, write)
@@ -924,7 +923,7 @@ def handleData(self, chunk):
             elif typebyte == NEG:
                 # -2**31 is too large for a positive int, so go through
                 # LongType first
-                obj = int(-long_type(header))
+                obj = int(-int(header))
             elif typebyte == LONGINT or typebyte == LONGNEG:
                 strlen = header
                 if len(self.buffer) >= strlen:
diff --git a/src/foolscap/broker.py b/src/foolscap/broker.py
index 6b23b8d..c6ca776 100644
--- a/src/foolscap/broker.py
+++ b/src/foolscap/broker.py
@@ -441,7 +441,7 @@ def getMyReferenceByCLID(self, clid):
         was registered with our Factory.
         """
 
-        assert isinstance(clid, six.integer_types)
+        assert isinstance(clid, int)
         if clid == 0:
             return self
         return self.myReferenceByCLID[clid].obj
@@ -451,7 +451,7 @@ def getMyReferenceByCLID(self, clid):
 
     def remote_decref(self, clid, count):
         # invoked when the other side sends us a decref message
-        assert isinstance(clid, six.integer_types)
+        assert isinstance(clid, int)
         assert clid != 0
         tracker = self.myReferenceByCLID.get(clid, None)
         if not tracker:
diff --git a/src/foolscap/constraint.py b/src/foolscap/constraint.py
index d484465..fab6ac5 100644
--- a/src/foolscap/constraint.py
+++ b/src/foolscap/constraint.py
@@ -5,7 +5,6 @@
 
 # This imports foolscap.tokens, but no other Foolscap modules.
 
-import six
 from zope.interface import implementer, Interface
 
 from foolscap.util import ensure_tuple_str
@@ -211,7 +210,7 @@ def __init__(self, maxLength=None, minLength=0):
                        VOCAB: None}
 
     def checkObject(self, obj, inbound):
-        if not isinstance(obj, six.binary_type):
+        if not isinstance(obj, bytes):
             raise Violation("'%r' is not a bytestring" % (obj,))
         if self.maxLength != None and len(obj) > self.maxLength:
             raise Violation("string too long (%d > %d)" %
@@ -236,7 +235,7 @@ def __init__(self, maxBytes=-1):
             self.taster[LONGNEG] = maxBytes
 
     def checkObject(self, obj, inbound):
-        if not isinstance(obj, six.integer_types):
+        if not isinstance(obj, int):
             raise Violation("'%r' is not a number" % (obj,))
         if self.maxBytes == -1:
             if obj >= 2**31 or obj < -2**31:
diff --git a/src/foolscap/logging/dumper.py b/src/foolscap/logging/dumper.py
index d7eff53..840665d 100644
--- a/src/foolscap/logging/dumper.py
+++ b/src/foolscap/logging/dumper.py
@@ -1,4 +1,4 @@
-import six, sys, errno, textwrap
+import sys, errno, textwrap
 from twisted.python import usage
 from foolscap.logging import flogfile
 from foolscap.logging.log import format_message
@@ -76,7 +76,7 @@ def print_header(self, e, options):
             t = h["trigger"]
             self.trigger = (t["incarnation"], t["num"])
         if options['verbose']:
-            print(six.text_type(e), file=stdout)
+            print(str(e), file=stdout)
         if not options["just-numbers"] and not options["verbose"]:
             if "versions" in h:
                 print(u"Application versions (embedded in logfile):", file=stdout)
@@ -95,7 +95,7 @@ def print_event(self, e, options):
         d = e['d']
         when = format_time(d['time'], options["timestamps"])
         if options['just-numbers']:
-            print(six.text_type(when), six.text_type(d.get('num')), file=stdout)
+            print(str(when), str(d.get('num')), file=stdout)
             return
 
         eid = (d["incarnation"], d["num"])
diff --git a/src/foolscap/logging/filter.py b/src/foolscap/logging/filter.py
index 69c5de7..66387d6 100644
--- a/src/foolscap/logging/filter.py
+++ b/src/foolscap/logging/filter.py
@@ -1,4 +1,3 @@
-import six
 from twisted.python import usage
 import sys, os, bz2, time
 from foolscap.logging import log, flogfile
@@ -82,7 +81,7 @@ def run(self, options):
         for e in flogfile.get_events(options.oldfile):
             if options['verbose']:
                 if "d" in e:
-                    print(six.text_type(e['d']['num']), file=stdout)
+                    print(str(e['d']['num']), file=stdout)
                 else:
                     print(u"HEADER", file=stdout)
             total += 1
diff --git a/src/foolscap/logging/gatherer.py b/src/foolscap/logging/gatherer.py
index 28898df..2f307dd 100644
--- a/src/foolscap/logging/gatherer.py
+++ b/src/foolscap/logging/gatherer.py
@@ -377,7 +377,7 @@ def maybe_fetch_incident(self):
             return
         self.incident_fetch_outstanding = True
         (name, trigger) = self.incidents_wanted.pop(0)
-        print("fetching incident", six.text_type(name), file=self.stdout)
+        print("fetching incident", str(name), file=self.stdout)
         d = self.publisher.callRemote("get_incident", six.ensure_binary(name))
         def _clear_outstanding(res):
             self.incident_fetch_outstanding = False
diff --git a/src/foolscap/logging/log.py b/src/foolscap/logging/log.py
index d0d1854..7a8fb9c 100644
--- a/src/foolscap/logging/log.py
+++ b/src/foolscap/logging/log.py
@@ -46,13 +46,13 @@ def format_message(e):
             args = e['args']
         elif "message" in e:
             fmt = "%(message)s"
-            assert isinstance(e['message'], (six.binary_type, six.text_type))
+            assert isinstance(e['message'], (bytes, str))
             args = {"message": six.ensure_str(e['message'])}
             # i.e. just return e['message']
         else:
             fmt = ""
             args = {}
-        assert isinstance(fmt, (six.binary_type, six.text_type))
+        assert isinstance(fmt, (bytes, str))
         return six.ensure_text(fmt % args)
     except (ValueError, TypeError):
         return six.ensure_text(e.get('message', "[no message]")) + " [formatting failed]"
@@ -380,9 +380,7 @@ def observer(self, d):
             # level.
             log_level = d.pop("log_level")
             new_log_level = llmap.get(log_level, log_level)
-            if not isinstance(new_log_level,
-                              six.integer_types +
-                              (six.binary_type, six.text_type, bool)):
+            if not isinstance(new_log_level, (int, bytes, str, bool)):
                 # it was something weird: just stringify it in-place
                 new_log_level = str(new_log_level)
             kwargs["level"] = new_log_level # foolscap level, not twisted
diff --git a/src/foolscap/logging/tail.py b/src/foolscap/logging/tail.py
index 4af072a..3330fe1 100644
--- a/src/foolscap/logging/tail.py
+++ b/src/foolscap/logging/tail.py
@@ -1,4 +1,4 @@
-import six, os, sys, time
+import os, sys, time
 from zope.interface import implementer
 from twisted.internet import reactor
 from twisted.python import usage
@@ -93,7 +93,7 @@ def remote_msg(self, d):
             self.saver.remote_msg(d)
 
     def simple_print(self, d):
-        print(six.text_type(d), file=self.output)
+        print(str(d), file=self.output)
 
     def formatted_print(self, d):
         time_s = format_time(d['time'], self.options["timestamps"])
diff --git a/src/foolscap/pb.py b/src/foolscap/pb.py
index 64df3a6..236b089 100644
--- a/src/foolscap/pb.py
+++ b/src/foolscap/pb.py
@@ -504,7 +504,7 @@ def listenOn(self, what, _test_options={}):
         @return: The Listener object that was created. This can be used to
         stop listening later on."""
 
-        if isinstance(what, (six.binary_type, six.text_type)):
+        if isinstance(what, (bytes, str)):
             what = six.ensure_str(what)
 
         if what in ("0", "tcp:0"):
diff --git a/src/foolscap/schema.py b/src/foolscap/schema.py
index 026e025..1e0b689 100644
--- a/src/foolscap/schema.py
+++ b/src/foolscap/schema.py
@@ -54,7 +54,6 @@
 
 """
 
-import six
 from foolscap.tokens import Violation, UnknownSchemaType, BananaError, \
      tokenNames
 
@@ -135,23 +134,20 @@ def AnyStringConstraint(*args, **kwargs):
 StringConstraint = ByteStringConstraint
 
 constraintMap = {
-    six.binary_type: ByteStringConstraint(),
-    six.text_type: UnicodeConstraint(),
+    bytes: ByteStringConstraint(),
+    str: UnicodeConstraint(),
     bool: BooleanConstraint(),
+    int: IntegerConstraint(maxBytes=1024),
     float: NumberConstraint(),
     None: Nothing(),
     }
 
-
 # we don't maintain compatibility for constraints defined by types. Back in
 # the py2-only days, 'int' meant a 32-bit signed integer, 'long' meant
 # fit-in-1024-bytes. The new rule is that 'int' means fit-in-1024-bytes (and
 # there is no 'long' in py3, of course). To get a 32-bit signed integer
 # constraint, use Int(maxBytes=-1).
 
-for t in six.integer_types:
-    constraintMap[t] = IntegerConstraint(maxBytes=1024)
-
 # This module provides a function named addToConstraintTypeMap() which helps
 # to resolve some import cycles.
 
diff --git a/src/foolscap/slicers/unicode.py b/src/foolscap/slicers/unicode.py
index 2944251..52634e9 100644
--- a/src/foolscap/slicers/unicode.py
+++ b/src/foolscap/slicers/unicode.py
@@ -1,6 +1,5 @@
 # -*- test-case-name: foolscap.test.test_banana -*-
 
-import six
 import re
 from twisted.internet.defer import Deferred
 from foolscap.tokens import BananaError, STRING, VOCAB, Violation
@@ -9,7 +8,7 @@
 
 class UnicodeSlicer(BaseSlicer):
     opentype = ("unicode",)
-    slices = six.text_type
+    slices = str
     def sliceBody(self, streamable, banana):
         yield self.obj.encode("UTF-8")
 
@@ -73,7 +72,7 @@ def __init__(self, maxLength=None, minLength=0, regexp=None):
             self.regexp = re.compile(regexp)
 
     def checkObject(self, obj, inbound):
-        if not isinstance(obj, six.text_type):
+        if not isinstance(obj, str):
             raise Violation("not a unicode object")
         if self.maxLength != None and len(obj) > self.maxLength:
             raise Violation("string too long (%d > %d)" %
diff --git a/src/foolscap/slicers/vocab.py b/src/foolscap/slicers/vocab.py
index 6523308..4b60fc7 100644
--- a/src/foolscap/slicers/vocab.py
+++ b/src/foolscap/slicers/vocab.py
@@ -32,7 +32,7 @@ def slice(self, streamable, banana):
         # flip here at the sending end.
         stringToIndex = self.obj
         for s in stringToIndex.keys():
-            assert isinstance(s, six.binary_type), "%r %s" % (s, type(s))
+            assert isinstance(s, bytes), "%r %s" % (s, type(s))
         indexToString = dict([(stringToIndex[s],s) for s in stringToIndex])
         assert len(stringToIndex) == len(indexToString) # catch duplicates
         indices = list(indexToString.keys())
diff --git a/src/foolscap/test/common.py b/src/foolscap/test/common.py
index e6e5699..f2f799a 100644
--- a/src/foolscap/test/common.py
+++ b/src/foolscap/test/common.py
@@ -1,6 +1,5 @@
 # -*- test-case-name: foolscap.test.test_pb -*-
 
-import six
 import time
 from zope.interface import implementer, implementer_only, implementedBy, Interface
 from twisted.python import log
@@ -16,7 +15,7 @@
      NumberConstraint, ByteStringConstraint, IntegerConstraint, \
      UnicodeConstraint, ChoiceOf
 from foolscap.referenceable import TubRef
-from foolscap.util import allocate_tcp_port, long_type
+from foolscap.util import allocate_tcp_port
 
 from twisted.python import failure
 from twisted.internet.main import CONNECTION_DONE
@@ -71,7 +70,7 @@ def getHost(self):
 
 MegaSchema1 = DictOf(ByteStringConstraint(),
                      ListOf(TupleOf(SetOf(int, maxLength=10, mutable=True),
-                                    six.binary_type, bool, int, long_type, float, None,
+                                    bytes, bool, int, float, None,
                                     UnicodeConstraint(),
                                     ByteStringConstraint(),
                                     Any(), NumberConstraint(),
diff --git a/src/foolscap/test/test_banana.py b/src/foolscap/test/test_banana.py
index c3fa860..f15baf8 100644
--- a/src/foolscap/test/test_banana.py
+++ b/src/foolscap/test/test_banana.py
@@ -14,7 +14,6 @@
 from foolscap.slicers.allslicers import RootSlicer, DictUnslicer, TupleUnslicer
 from foolscap.constraint import IConstraint
 from foolscap.banana import int2b128, long_to_bytes
-from ..util import long_type
 
 import io
 import struct
@@ -123,7 +122,7 @@ def untokenize(tokens):
             else:
                 raise RuntimeError("bad token")
         else:
-            if isinstance(t, six.integer_types):
+            if isinstance(t, int):
                 if t >= 2**31:
                     s = long_to_bytes(t)
                     int2b128(len(s), data.append)
@@ -143,7 +142,7 @@ def untokenize(tokens):
             elif isinstance(t, float):
                 data.append(FLOAT)
                 data.append(struct.pack("!d", t))
-            elif isinstance(t, six.string_types) or isinstance(t, six.binary_type):
+            elif isinstance(t, six.string_types) or isinstance(t, bytes):
                 t = six.ensure_binary(t)
                 int2b128(len(t), data.append)
                 data.append(STRING)
@@ -1215,14 +1214,6 @@ def testInt(self):
         self.check(-1, bINT(-1))
         self.check(-127, bINT(-127))
 
-    def testLong(self):
-        self.check(long_type(258), b"\x02\x85\x01\x02") # TODO: 0x85 for LONGINT??
-        self.check(long_type(-258), b"\x02\x86\x01\x02") # TODO: 0x85 for LONGINT??
-        self.check(long_type(0), b"\x85")
-        self.check(long_type(0), b"\x00\x85")
-        self.check(long_type(0), b"\x86")
-        self.check(long_type(0), b"\x00\x86")
-
     def testString(self):
         self.check(b"", b"\x82")
         self.check(b"", b"\x00\x82")
@@ -1513,18 +1504,18 @@ def test_int(self):
     def test_bigint(self):
         # some of these are small enough to fit in an INT
         d = self.looptest(int(2**31-1)) # most positive representable INT
-        d.addCallback(lambda res: self.looptest(long_type(2**31+0)))
-        d.addCallback(lambda res: self.looptest(long_type(2**31+1)))
+        d.addCallback(lambda res: self.looptest(2**31+0))
+        d.addCallback(lambda res: self.looptest(2**31+1))
 
-        d.addCallback(lambda res: self.looptest(long_type(-2**31-1)))
+        d.addCallback(lambda res: self.looptest(-2**31-1))
         # the following is the most negative representable INT
-        d.addCallback(lambda res: self.looptest(int(-2**31+0)))
-        d.addCallback(lambda res: self.looptest(int(-2**31+1)))
+        d.addCallback(lambda res: self.looptest(-2**31+0))
+        d.addCallback(lambda res: self.looptest(-2**31+1))
 
-        d.addCallback(lambda res: self.looptest(long_type(2**100)))
-        d.addCallback(lambda res: self.looptest(long_type(-2**100)))
-        d.addCallback(lambda res: self.looptest(long_type(2**1000)))
-        d.addCallback(lambda res: self.looptest(long_type(-2**1000)))
+        d.addCallback(lambda res: self.looptest(2**100))
+        d.addCallback(lambda res: self.looptest(-2**100))
+        d.addCallback(lambda res: self.looptest(2**1000))
+        d.addCallback(lambda res: self.looptest(-2**1000))
         return d
 
     def test_decimal(self):
@@ -1592,7 +1583,7 @@ def _testIdentity_1(self, z):
         self.assertIdentical(z[0][0], z)
 
     def testUnicode(self):
-        x = [six.text_type('blah')]
+        x = ['blah']
         d = self.loop(x)
         d.addCallback(self._testUnicode_1, x)
         return d
diff --git a/src/foolscap/test/test_call.py b/src/foolscap/test/test_call.py
index 05936aa..056cde7 100644
--- a/src/foolscap/test/test_call.py
+++ b/src/foolscap/test/test_call.py
@@ -21,7 +21,6 @@
 from foolscap.api import RemoteException, DeadReferenceError
 from foolscap.call import CopiedFailure
 from foolscap.logging import log as flog
-from ..util import long_type
 
 class Unsendable:
     pass
@@ -221,7 +220,7 @@ def testMegaSchema(self):
         # try to exercise all our constraints at once
         rr, target = self.setupTarget(HelperTarget())
         t = (set([1, 2, 3]),
-             b"str", True, 12, long_type(12), 19.3, None,
+             b"str", True, 12, 19.3, None,
              u"unicode",
              b"bytestring",
              "any", 14.3,
diff --git a/src/foolscap/test/test_schema.py b/src/foolscap/test/test_schema.py
index 636d9b1..16fc456 100644
--- a/src/foolscap/test/test_schema.py
+++ b/src/foolscap/test/test_schema.py
@@ -1,4 +1,3 @@
-import six
 import re
 from twisted.trial import unittest
 from foolscap import schema, copyable, broker
@@ -101,7 +100,7 @@ def testUnicode(self):
         self.violates(c4, b"I'm a bytestring")
         self.violates(c4, u"spelled entirely without those letters")
         self.conforms(c4, u"add better cases")
-        c5 = schema.UnicodeConstraint(regexp=re.compile("\d+\s\w+"))
+        c5 = schema.UnicodeConstraint(regexp=re.compile(r"\d+\s\w+"))
         self.violates(c5, b"I'm a bytestring")
         self.conforms(c5, u": 123 boo")
         self.violates(c5, u"more than 1  spaces")
@@ -279,7 +278,7 @@ def testMakeConstraint(self):
         self.check(c, schema.IntegerConstraint)
         self.failUnlessEqual(c.maxBytes, 1024)
 
-        c = make(six.binary_type)
+        c = make(bytes)
         self.check(c, schema.ByteStringConstraint)
         self.failUnlessEqual(c.maxLength, None)
 
@@ -287,7 +286,7 @@ def testMakeConstraint(self):
         self.check(c, schema.ByteStringConstraint)
         self.failUnlessEqual(c.maxLength, 2000)
 
-        c = make(six.text_type)
+        c = make(str)
         self.check(c, schema.UnicodeConstraint)
         self.failUnlessEqual(c.maxLength, None)
 
diff --git a/src/foolscap/util.py b/src/foolscap/util.py
index b8d84df..a3abedc 100644
--- a/src/foolscap/util.py
+++ b/src/foolscap/util.py
@@ -201,12 +201,6 @@ def _make_socket():
         s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     return s
 
-# long_type(0) is 0L on py2, just plain 0 on py3
-if len(six.integer_types) > 1:
-    long_type = [t for t in six.integer_types if t is not int][0]
-else:
-    long_type = int
-
 def ensure_tuple_str(input_tuple):
     return tuple([six.ensure_str(s) for s in input_tuple])