diff --git a/joy/gui/init_joy_home.py b/joy/gui/init_joy_home.py
index 691cba3..4a40072 100644
--- a/joy/gui/init_joy_home.py
+++ b/joy/gui/init_joy_home.py
@@ -9,6 +9,7 @@ file, so you can just do, e.g.:
     init_joy_home.initialize(JOY_HOME)
 
 '''
+from __future__ import print_function
 import base64, os, StringIO, zipfile
 
 
@@ -100,4 +101,4 @@ AAAAAAAAAAAAtIH2BgAAZGVmaW5pdGlvbnMudHh0UEsFBgAAAAAFAAUAHgEAAF0OAAAAAA==''')))
 
 
 if __name__ == '__main__':
-    print create_data()
+    print(create_data())
diff --git a/joy/gui/main.py b/joy/gui/main.py
index eb84be4..61aa77e 100755
--- a/joy/gui/main.py
+++ b/joy/gui/main.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
+from __future__ import print_function
 ('''\
 Joypy - Copyright © 2018 Simon Forman
 '''
@@ -61,12 +62,12 @@ def commands():
       ]
     for key, command in GLOBAL_COMMANDS.iteritems():
       commands.append('%s - %s' % (key.lstrip('<').rstrip('>'), command))
-    print '\n'.join([''] + sorted(commands))
+    print('\n'.join([''] + sorted(commands)))
     return args
 
 
   def mouse_bindings(*args):
-    print dedent('''
+    print(dedent('''
       Mouse button chords (to cancel a chord, click the third mouse button.)
 
       Left - Point, sweep selection
@@ -80,13 +81,13 @@ def commands():
       Right - Execute command word under mouse cursor
       Right-Left - Print docs of command word under mouse cursor
       Right-Middle - Lookup word (kinda useless now)
-      ''')
+      '''))
     return args
 
 
   def reset_log(*args):
     log.delete('0.0', tk.END)
-    print __doc__
+    print(__doc__)
     return args
 
 
diff --git a/joy/gui/textwidget.py b/joy/gui/textwidget.py
index 08c1734..1dc4f43 100644
--- a/joy/gui/textwidget.py
+++ b/joy/gui/textwidget.py
@@ -120,7 +120,7 @@ class SavingMixin:
     if not self.filename:
       return
     with open(self.filename, 'w') as f:
-      os.chmod(self.filename, 0600)
+      os.chmod(self.filename, 0o600)
       f.write(text.encode('UTF_8'))
       f.flush()
       os.fsync(f.fileno())
diff --git a/joy/gui/utils.py b/joy/gui/utils.py
index e187d12..ef0a2d0 100644
--- a/joy/gui/utils.py
+++ b/joy/gui/utils.py
@@ -1,3 +1,4 @@
+from __future__ import print_function
 import argparse, os, sys
 from os import listdir, mkdir
 from os.path import abspath, exists, expanduser, isfile, join
@@ -25,10 +26,10 @@ def home_dir(path):
 
   if not exists(fullpath):
     if path == DEFAULT_JOY_HOME:
-      print 'Creating JOY_HOME', repr(fullpath)
-      mkdir(fullpath, 0700)
+      print('Creating JOY_HOME', repr(fullpath))
+      mkdir(fullpath, 0o700)
     else:
-      print >> sys.stderr, repr(fullpath), "doesn't exist."
+      print(repr(fullpath), "doesn't exist.", file=sys.stderr)
       raise ValueError(path)
 
   return fullpath
@@ -42,16 +43,16 @@ def init_home(fullpath):
   try:
     repo = Repo(fullpath)
   except NotGitRepository:
-    print >> sys.stderr, repr(fullpath), "no repository"
+    print(repr(fullpath), "no repository", file=sys.stderr)
 
     if listdir(fullpath):
-      print >> sys.stderr, repr(fullpath), "has contents\nQUIT."
+      print(repr(fullpath), "has contents\nQUIT.", file=sys.stderr)
       sys.exit(2)
 
-    print 'Initializing repository in', fullpath
+    print('Initializing repository in', fullpath)
     repo = init_repo(fullpath)
 
-  print 'Using repository in', fullpath
+  print('Using repository in', fullpath)
   return repo
 
 
diff --git a/joy/gui/world.py b/joy/gui/world.py
index 14c8dac..a06d9a8 100644
--- a/joy/gui/world.py
+++ b/joy/gui/world.py
@@ -17,6 +17,7 @@
 #    You should have received a copy of the GNU General Public License
 #    along with joy.py.  If not see <http://www.gnu.org/licenses/>.
 #
+from __future__ import print_function
 from logging import getLogger
 
 _log = getLogger(__name__)
@@ -57,14 +58,14 @@ class World(object):
 
   def do_opendoc(self, name):
     if is_numerical(name):
-      print 'The number', name
+      print('The number', name)
     else:
       try:
         word = self.dictionary[name]
       except KeyError:
-        print repr(name), '???'
+        print(repr(name), '???')
       else:
-        print getdoc(word)
+        print(getdoc(word))
     self.print_stack()
 
   def pop(self):
@@ -99,7 +100,7 @@ class World(object):
       self.check_cache.clear()
 
   def has(self, name):
-    return self.dictionary.has_key(name)
+    return name in self.dictionary
 
   def save(self):
     pass
@@ -125,15 +126,15 @@ class StackDisplayWorld(World):
     command = command.strip()
     if self.has(command) and self.check(command) == False:  # not in {True, None}:
       return
-    print '\njoy?', command
+    print('\njoy?', command)
     super(StackDisplayWorld, self).interpret(command)
 
   def print_stack(self):
-    print '\n%s <-' % stack_to_string(self.stack)
+    print('\n%s <-' % stack_to_string(self.stack))
 
   def save(self):
     with open(self.filename, 'wb') as f:
-      os.chmod(self.filename, 0600)
+      os.chmod(self.filename, 0o600)
       pickle.dump(self.stack, f)
       f.flush()
       os.fsync(f.fileno())