diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..401eb52
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,12 @@
+*.pyc
+*.so
+*.dll
+__pycache__
+src/*.egg-info
+
+.installed.cfg
+.tox
+bin
+build
+develop-eggs
+parts
diff --git a/CHANGES.txt b/CHANGES.txt
index 8b17f6a..a4c3ac5 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,10 +1,11 @@
 Changes
 =======
 
-
 4.0.0 (unreleased)
 ------------------
 
+- Added support for Python 3.3.
+
 - Dropped support for Python 2.4 and 2.5.
 
 
diff --git a/MANIFEST.in b/MANIFEST.in
new file mode 100644
index 0000000..e9ec60d
--- /dev/null
+++ b/MANIFEST.in
@@ -0,0 +1,11 @@
+include *.rst
+include *.txt
+include *.py
+include buildout.cfg
+include tox.ini
+
+recursive-include src *
+
+global-exclude *.pyc
+global-exclude *.so
+global-exclude *.dll
diff --git a/bootstrap.py b/bootstrap.py
index a6da5d3..ec3757a 100644
--- a/bootstrap.py
+++ b/bootstrap.py
@@ -18,102 +18,148 @@
 use the -c option to specify an alternate configuration file.
 """
 
-import os, shutil, sys, tempfile, urllib2
+import os, shutil, sys, tempfile
 from optparse import OptionParser
 
 tmpeggs = tempfile.mkdtemp()
 
-is_jython = sys.platform.startswith('java')
+usage = '''\
+[DESIRED PYTHON FOR BUILDOUT] bootstrap.py [options]
 
-# parsing arguments
-parser = OptionParser()
-parser.add_option("-v", "--version", dest="version",
-                          help="use a specific zc.buildout version")
-parser.add_option("-d", "--distribute",
-                   action="store_true", dest="distribute", default=False,
-                   help="Use Disribute rather than Setuptools.")
+Bootstraps a buildout-based project.
 
-parser.add_option("-c", None, action="store", dest="config_file",
+Simply run this script in a directory containing a buildout.cfg, using the
+Python that you want bin/buildout to use.
+
+Note that by using --setup-source and --download-base to point to
+local resources, you can keep this script from going over the network.
+'''
+
+parser = OptionParser(usage=usage)
+parser.add_option("-v", "--version", help="use a specific zc.buildout version")
+
+parser.add_option("-t", "--accept-buildout-test-releases",
+                  dest='accept_buildout_test_releases',
+                  action="store_true", default=False,
+                  help=("Normally, if you do not specify a --version, the "
+                        "bootstrap script and buildout gets the newest "
+                        "*final* versions of zc.buildout and its recipes and "
+                        "extensions for you.  If you use this flag, "
+                        "bootstrap and buildout will get the newest releases "
+                        "even if they are alphas or betas."))
+parser.add_option("-c", "--config-file",
                    help=("Specify the path to the buildout configuration "
                          "file to be used."))
+parser.add_option("-f", "--find-links",
+                   help=("Specify a URL to search for buildout releases"))
 
-options, args = parser.parse_args()
-
-# if -c was provided, we push it back into args for buildout' main function
-if options.config_file is not None:
-    args += ['-c', options.config_file]
 
-if options.version is not None:
-    VERSION = '==%s' % options.version
-else:
-    VERSION = ''
+options, args = parser.parse_args()
 
-USE_DISTRIBUTE = options.distribute
-args = args + ['bootstrap']
+######################################################################
+# load/install distribute
 
 to_reload = False
 try:
-    import pkg_resources
+    import pkg_resources, setuptools
     if not hasattr(pkg_resources, '_distribute'):
         to_reload = True
         raise ImportError
 except ImportError:
     ez = {}
-    if USE_DISTRIBUTE:
-        exec urllib2.urlopen('http://python-distribute.org/distribute_setup.py'
-                         ).read() in ez
-        ez['use_setuptools'](to_dir=tmpeggs, download_delay=0, no_fake=True)
-    else:
-        exec urllib2.urlopen('http://peak.telecommunity.com/dist/ez_setup.py'
-                             ).read() in ez
-        ez['use_setuptools'](to_dir=tmpeggs, download_delay=0)
+
+    try:
+        from urllib.request import urlopen
+    except ImportError:
+        from urllib2 import urlopen
+
+    exec(urlopen('http://python-distribute.org/distribute_setup.py').read(), ez)
+    setup_args = dict(to_dir=tmpeggs, download_delay=0, no_fake=True)
+    ez['use_setuptools'](**setup_args)
 
     if to_reload:
         reload(pkg_resources)
-    else:
-        import pkg_resources
-
-if sys.platform == 'win32':
-    def quote(c):
-        if ' ' in c:
-            return '"%s"' % c # work around spawn lamosity on windows
-        else:
-            return c
-else:
-    def quote (c):
-        return c
-
-cmd = 'from setuptools.command.easy_install import main; main()'
+    import pkg_resources
+    # This does not (always?) update the default working set.  We will
+    # do it.
+    for path in sys.path:
+        if path not in pkg_resources.working_set.entries:
+            pkg_resources.working_set.add_entry(path)
+
+######################################################################
+# Install buildout
+
 ws  = pkg_resources.working_set
 
-if USE_DISTRIBUTE:
-    requirement = 'distribute'
-else:
-    requirement = 'setuptools'
-
-if is_jython:
-    import subprocess
-
-    assert subprocess.Popen([sys.executable] + ['-c', quote(cmd), '-mqNxd',
-           quote(tmpeggs), 'zc.buildout' + VERSION],
-           env=dict(os.environ,
-               PYTHONPATH=
-               ws.find(pkg_resources.Requirement.parse(requirement)).location
-               ),
-           ).wait() == 0
-
-else:
-    assert os.spawnle(
-        os.P_WAIT, sys.executable, quote (sys.executable),
-        '-c', quote (cmd), '-mqNxd', quote (tmpeggs), 'zc.buildout' + VERSION,
-        dict(os.environ,
-            PYTHONPATH=
-            ws.find(pkg_resources.Requirement.parse(requirement)).location
-            ),
-        ) == 0
+cmd = [sys.executable, '-c',
+       'from setuptools.command.easy_install import main; main()',
+       '-mZqNxd', tmpeggs]
+
+find_links = os.environ.get(
+    'bootstrap-testing-find-links',
+    options.find_links or
+    ('http://downloads.buildout.org/'
+     if options.accept_buildout_test_releases else None)
+    )
+if find_links:
+    cmd.extend(['-f', find_links])
+
+distribute_path = ws.find(
+    pkg_resources.Requirement.parse('distribute')).location
+
+requirement = 'zc.buildout'
+version = options.version
+if version is None and not options.accept_buildout_test_releases:
+    # Figure out the most recent final version of zc.buildout.
+    import setuptools.package_index
+    _final_parts = '*final-', '*final'
+    def _final_version(parsed_version):
+        for part in parsed_version:
+            if (part[:1] == '*') and (part not in _final_parts):
+                return False
+        return True
+    index = setuptools.package_index.PackageIndex(
+        search_path=[distribute_path])
+    if find_links:
+        index.add_find_links((find_links,))
+    req = pkg_resources.Requirement.parse(requirement)
+    if index.obtain(req) is not None:
+        best = []
+        bestv = None
+        for dist in index[req.project_name]:
+            distv = dist.parsed_version
+            if _final_version(distv):
+                if bestv is None or distv > bestv:
+                    best = [dist]
+                    bestv = distv
+                elif distv == bestv:
+                    best.append(dist)
+        if best:
+            best.sort()
+            version = best[-1].version
+if version:
+    requirement = '=='.join((requirement, version))
+cmd.append(requirement)
+
+import subprocess
+if subprocess.call(cmd, env=dict(os.environ, PYTHONPATH=distribute_path)) != 0:
+    raise Exception(
+        "Failed to execute command:\n%s",
+        repr(cmd)[1:-1])
+
+######################################################################
+# Import and run buildout
 
 ws.add_entry(tmpeggs)
-ws.require('zc.buildout' + VERSION)
+ws.require(requirement)
 import zc.buildout.buildout
+
+if not [a for a in args if '=' not in a]:
+    args.append('bootstrap')
+
+# if -c was provided, we push it back into args for buildout' main function
+if options.config_file is not None:
+    args[0:0] = ['-c', options.config_file]
+
 zc.buildout.buildout.main(args)
 shutil.rmtree(tmpeggs)
diff --git a/buildout.cfg b/buildout.cfg
index 8cbd6da..c1df359 100644
--- a/buildout.cfg
+++ b/buildout.cfg
@@ -1,7 +1,12 @@
 [buildout]
-parts = test
+parts = py test
 develop = .
 
 [test]
 recipe = zc.recipe.testrunner
 eggs = zope.deferredimport [test]
+
+[py]
+recipe = zc.recipe.egg
+eggs = zope.deferredimport [test]
+interpreter = py
diff --git a/setup.py b/setup.py
index 67a52ef..4fd0bae 100644
--- a/setup.py
+++ b/setup.py
@@ -18,20 +18,35 @@
 ##############################################################################
 """Setup for zope.deferredimport package
 """
-
 import os
 from setuptools import setup, find_packages
 
 def read(*rnames):
     return open(os.path.join(os.path.dirname(__file__), *rnames)).read()
 
+def alltests():
+    import os
+    import sys
+    import unittest
+    # use the zope.testrunner machinery to find all the
+    # test suites we've put under ourselves
+    import zope.testrunner.find
+    import zope.testrunner.options
+    here = os.path.abspath(os.path.join(os.path.dirname(__file__), 'src'))
+    args = sys.argv[:]
+    defaults = ["--test-path", here]
+    options = zope.testrunner.options.get_options(args, defaults)
+    suites = list(zope.testrunner.find.find_suites(options))
+    return unittest.TestSuite(suites)
+
+
 setup(
     name='zope.deferredimport',
     version='4.0.0dev',
     url='http://pypi.python.org/pypi/zope.deferredimport',
     license='ZPL 2.1',
-    description='zope.deferredimport allows you to perform imports names '
-    'that will only be resolved when used in the code.',
+    description=('zope.deferredimport allows you to perform imports names '
+                 'that will only be resolved when used in the code.'),
     author='Zope Foundation and Contributors',
     author_email='zope-dev@zope.org',
     long_description=(
@@ -52,6 +67,9 @@ def read(*rnames):
         'Programming Language :: Python :: 2',
         'Programming Language :: Python :: 2.6',
         'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.3',
+        'Programming Language :: Python :: Implementation :: CPython',
         'Natural Language :: English',
         'Operating System :: OS Independent',
         'Topic :: Internet :: WWW/HTTP',
@@ -68,6 +86,8 @@ def read(*rnames):
         test=[
             'zope.testing',
             ]),
+    tests_require=['zope.testing', 'zope.testrunner'],
+    test_suite = '__main__.alltests',
     include_package_data = True,
     zip_safe = False,
     )
diff --git a/src/zope/deferredimport/README.txt b/src/zope/deferredimport/README.txt
index b83e28b..96f5b7d 100644
--- a/src/zope/deferredimport/README.txt
+++ b/src/zope/deferredimport/README.txt
@@ -23,7 +23,7 @@ that defined some things to be imported:
 
     >>> create_module(sample1 = '''
     ...
-    ... print "Sampe 1 imported!"
+    ... print("Sampe 1 imported!")
     ...
     ... x = 1
     ...
@@ -68,7 +68,7 @@ imported.  When we import sample2, we don't see a message until we
 access a variable:
 
     >>> import zope.deferredimport.sample2
-    >>> print zope.deferredimport.sample2.one
+    >>> print(zope.deferredimport.sample2.one)
     Sampe 1 imported!
     1
 
@@ -128,7 +128,6 @@ more complicated example.
     ... ''')
 
     >>> create_module(sample4 = '''
-    ...
     ... import sample3
     ...
     ... def getone():
@@ -141,23 +140,25 @@ sample3 is imported, it imports sample 4, which then imports sample3.
 Let's see what happens when we use these modules in an unfortunate
 order:
 
-    >>> import zope.deferredimport.sample3
-    >>> import zope.deferredimport.sample4
-
-    >>> zope.deferredimport.sample4.getone()
-    Traceback (most recent call last):
-    ...
-    AttributeError: 'module' object has no attribute 'one'
-
-Hm.  Let's try accessing one through sample3:
-
-    >>> zope.deferredimport.sample3.one
-    1
-
-Funny, let's try getone again:
-
-    >>> zope.deferredimport.sample4.getone()
-    1
+# XXX: Relative imports like this are not possible on Python 3 anymore.
+
+#    >>> import zope.deferredimport.sample3
+#    >>> import zope.deferredimport.sample4
+#
+#    >>> zope.deferredimport.sample4.getone()
+#    Traceback (most recent call last):
+#    ...
+#    AttributeError: 'module' object has no attribute 'one'
+#
+#Hm.  Let's try accessing one through sample3:
+#
+#    >>> zope.deferredimport.sample3.one
+#    1
+#
+#Funny, let's try getone again:
+#
+#    >>> zope.deferredimport.sample4.getone()
+#    1
 
 The problem is that sample4 obtained sample3 before sample4 was
 replaced by a proxy.  This example is slightly pathological because it
@@ -167,7 +168,6 @@ deferred imports before importing any other modules.  Alternatively,
 you can call the initialize function before importing any other
 modules, as in:
 
-
     >>> create_module(sample5 = '''
     ...
     ... import zope.deferredimport
@@ -187,10 +187,10 @@ modules, as in:
 
     >>> create_module(sample6 = '''
     ...
-    ... import sample5
+    ... import zope.deferredimport.sample5
     ...
     ... def getone():
-    ...     return sample5.one
+    ...     return zope.deferredimport.sample5.one
     ...
     ... ''')
 
@@ -228,8 +228,7 @@ Now, if we use one of these variables, we'll get a deprecation
 warning:
 
     >>> import zope.deferredimport.sample7
-    >>> zope.deferredimport.sample7.x
-    ... doctest: +NORMALIZE_WHITESPACE
+    >>> zope.deferredimport.sample7.x # doctest: +NORMALIZE_WHITESPACE
     zope/deferredimport/README.txt:1: DeprecationWarning:
                 x is deprecated. Import from sample1 instead
       Deferred Import
@@ -265,13 +264,12 @@ can use defineFrom or deprecatedFrom to do that:
     ... ''')
 
     >>> create_module(sample9 = '''
-    ... print 'Imported sample 9'
+    ... print('Imported sample 9')
     ... a, b, c = range(10,13)
     ... ''')
 
     >>> import zope.deferredimport.sample8
-    >>> zope.deferredimport.sample8.q
-    ... doctest: +NORMALIZE_WHITESPACE
+    >>> zope.deferredimport.sample8.q #doctest: +NORMALIZE_WHITESPACE
     zope/deferredimport/README.txt:1: DeprecationWarning:
             q is deprecated. Import from sample1 instead
       Deferred Import
diff --git a/src/zope/deferredimport/deferredmodule.py b/src/zope/deferredimport/deferredmodule.py
index 72d28ed..3df4a87 100644
--- a/src/zope/deferredimport/deferredmodule.py
+++ b/src/zope/deferredimport/deferredmodule.py
@@ -50,7 +50,7 @@ def get(self):
         warnings.warn(
             self.__name__ + " is deprecated. " + self.message,
             DeprecationWarning, stacklevel=3)
-        
+
         return super(DeferredAndDeprecated, self).get()
 
 
@@ -65,7 +65,7 @@ def __getattr__(self, name):
         try:
             get = self.__deferred_definitions__.pop(name)
         except KeyError:
-            raise AttributeError, name
+            raise AttributeError(name)
         v = get.get()
         setattr(self, name, v)
         return v
@@ -108,7 +108,7 @@ def define(**names):
     """
     module = initialize(2)
     __deferred_definitions__ = module.__deferred_definitions__
-    for name, specifier in names.iteritems():
+    for name, specifier in names.items():
         __deferred_definitions__[name] = Deferred(name, specifier)
 
 def defineFrom(from_name, *names):
@@ -135,7 +135,7 @@ def deprecated(message, **names):
     """
     module = initialize(2)
     __deferred_definitions__ = module.__deferred_definitions__
-    for name, specifier in names.iteritems():
+    for name, specifier in names.items():
         __deferred_definitions__[name] = DeferredAndDeprecated(
             name, specifier, message)
 
diff --git a/src/zope/deferredimport/samples/__init__.py b/src/zope/deferredimport/samples/__init__.py
new file mode 100644
index 0000000..874c802
--- /dev/null
+++ b/src/zope/deferredimport/samples/__init__.py
@@ -0,0 +1 @@
+# Make a package.
diff --git a/src/zope/deferredimport/samples/sample1.py b/src/zope/deferredimport/samples/sample1.py
new file mode 100644
index 0000000..9acb885
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample1.py
@@ -0,0 +1,12 @@
+
+
+print("Sampe 1 imported!")
+
+x = 1
+
+class C:
+    y = 2
+
+z = 3
+q = 4
+
diff --git a/src/zope/deferredimport/samples/sample2.py b/src/zope/deferredimport/samples/sample2.py
new file mode 100644
index 0000000..b2cc3f1
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample2.py
@@ -0,0 +1,15 @@
+
+
+import zope.deferredimport
+
+zope.deferredimport.define(
+    sample1 = 'zope.deferredimport.sample1',
+    one = 'zope.deferredimport.sample1:x',
+    two = 'zope.deferredimport.sample1:C.y',
+    )
+
+three = 3
+x = 4
+def getx():
+    return x
+
diff --git a/src/zope/deferredimport/samples/sample3.py b/src/zope/deferredimport/samples/sample3.py
new file mode 100644
index 0000000..044bfff
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample3.py
@@ -0,0 +1,13 @@
+
+
+import zope.deferredimport
+import zope.deferredimport.sample4
+
+zope.deferredimport.define(
+    sample1 = 'zope.deferredimport.sample1',
+    one = 'zope.deferredimport.sample1:x',
+    two = 'zope.deferredimport.sample1:C.y',
+    )
+
+x = 1
+
diff --git a/src/zope/deferredimport/samples/sample4.py b/src/zope/deferredimport/samples/sample4.py
new file mode 100644
index 0000000..32c3ecd
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample4.py
@@ -0,0 +1,6 @@
+
+import sample3
+
+def getone():
+    return sample3.one
+
diff --git a/src/zope/deferredimport/samples/sample5.py b/src/zope/deferredimport/samples/sample5.py
new file mode 100644
index 0000000..3103fed
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample5.py
@@ -0,0 +1,15 @@
+
+
+import zope.deferredimport
+zope.deferredimport.initialize()
+
+import zope.deferredimport.sample6
+
+zope.deferredimport.define(
+    sample1 = 'zope.deferredimport.sample1',
+    one = 'zope.deferredimport.sample1:x',
+    two = 'zope.deferredimport.sample1:C.y',
+    )
+
+x = 1
+
diff --git a/src/zope/deferredimport/samples/sample6.py b/src/zope/deferredimport/samples/sample6.py
new file mode 100644
index 0000000..6528fee
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample6.py
@@ -0,0 +1,7 @@
+
+
+import zope.deferredimport.sample5
+
+def getone():
+    return zope.deferredimport.sample5.one
+
diff --git a/src/zope/deferredimport/samples/sample7.py b/src/zope/deferredimport/samples/sample7.py
new file mode 100644
index 0000000..a6a669e
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample7.py
@@ -0,0 +1,12 @@
+
+
+import zope.deferredimport
+zope.deferredimport.initialize()
+
+zope.deferredimport.deprecated(
+    "Import from sample1 instead",
+    x = 'zope.deferredimport.sample1:x',
+    y = 'zope.deferredimport.sample1:C.y',
+    z = 'zope.deferredimport.sample1:z',
+    )
+
diff --git a/src/zope/deferredimport/samples/sample8.py b/src/zope/deferredimport/samples/sample8.py
new file mode 100644
index 0000000..f9f3c9f
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample8.py
@@ -0,0 +1,15 @@
+
+
+import zope.deferredimport
+
+zope.deferredimport.deprecatedFrom(
+    "Import from sample1 instead",
+    'zope.deferredimport.sample1',
+    'x', 'z', 'q',
+    )
+
+zope.deferredimport.defineFrom(
+    'zope.deferredimport.sample9',
+    'a', 'b', 'c',
+    )
+
diff --git a/src/zope/deferredimport/samples/sample9.py b/src/zope/deferredimport/samples/sample9.py
new file mode 100644
index 0000000..c570156
--- /dev/null
+++ b/src/zope/deferredimport/samples/sample9.py
@@ -0,0 +1,3 @@
+
+print('Imported sample 9')
+a, b, c = range(10,13)
diff --git a/src/zope/deferredimport/tests.py b/src/zope/deferredimport/tests.py
index 7dd8659..e8a4e97 100644
--- a/src/zope/deferredimport/tests.py
+++ b/src/zope/deferredimport/tests.py
@@ -11,7 +11,8 @@
 # FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
-
+"""Tests
+"""
 import doctest
 import os
 import re
@@ -38,29 +39,38 @@ def warn(message, type_, stacklevel):
     lineno = frame.f_lineno
     for i in range(lineno):
         line = file.readline()
+    file.close()
 
-    print "%s:%s: %s: %s\n  %s" % (
+    print("%s:%s: %s: %s\n  %s" % (
         path,
         frame.f_lineno,
         type_.__name__,
         message,
         line.strip(),
-        )
+        ))
 
 
 def setUp(test):
-    d = test.globs['tmp_d'] = tempfile.mkdtemp('deferredimport')
+    # Py3: The old method of creating a tempdir and adding it to the
+    # module.__path__ does not work reliably in Python 3.3.
+    d = test.globs['tmp_d'] = os.path.join(os.path.dirname(__file__), 'samples')
 
     def create_module(**modules):
-        for name, src in modules.iteritems():
-            f = open(os.path.join(d, name+'.py'), 'w')
-            f.write(src)
-            f.close()
+        for name, src in modules.items():
+            fn = os.path.join(d, name+'.py')
+            needs_update = True
+            if os.path.exists(fn):
+                with open(fn, 'r') as file:
+                    needs_update = file.read() != src
+            if needs_update:
+                with open(fn, 'w') as file:
+                    file.write(src)
             test.globs['created_modules'].append(name)
 
     test.globs['created_modules'] = []
     test.globs['create_module'] = create_module
 
+    import zope.deferredimport
     zope.deferredimport.__path__.append(d)
 
     test.globs['oldstderr'] = sys.stderr
@@ -69,12 +79,10 @@ def create_module(**modules):
     test.globs['saved_warn'] = warnings.warn
     warnings.warn = warn
 
-
 def tearDown(test):
     sys.stderr = test.globs['oldstderr']
 
     zope.deferredimport.__path__.pop()
-    shutil.rmtree(test.globs['tmp_d'])
     for name in test.globs['created_modules']:
         sys.modules.pop(name, None)
     warnings.warn = test.globs['saved_warn']
@@ -89,5 +97,6 @@ def test_suite():
         setUp=setUp, tearDown=tearDown,
         optionflags=doctest.NORMALIZE_WHITESPACE,
         checker=checker,
-        globs = {'__file__': os.path.join(os.path.dirname(__file__), 'README.txt')}
+        globs = {'__file__': os.path.join(
+                    os.path.dirname(__file__), 'README.txt')}
         )
diff --git a/tox.ini b/tox.ini
new file mode 100644
index 0000000..5dd2b88
--- /dev/null
+++ b/tox.ini
@@ -0,0 +1,11 @@
+[tox]
+envlist =
+    py26,py27,py33
+
+[testenv]
+commands =
+    python setup.py test -q
+deps =
+    zope.proxy
+    zope.testing
+    zope.testrunner