diff --git a/openphoto/__init__.py b/openphoto/__init__.py
index ce569c5..67eb995 100644
--- a/openphoto/__init__.py
+++ b/openphoto/__init__.py
@@ -1,8 +1,8 @@
-from openphoto_http import OpenPhotoHttp
-from errors import *
-import api_photo
-import api_tag
-import api_album
+from .openphoto_http import OpenPhotoHttp
+from .errors import *
+from . import api_photo
+from . import api_tag
+from . import api_album
 
 LATEST_API_VERSION = 2
 
diff --git a/openphoto/api_album.py b/openphoto/api_album.py
index 9777a30..96a31b3 100644
--- a/openphoto/api_album.py
+++ b/openphoto/api_album.py
@@ -1,5 +1,5 @@
-from errors import *
-from objects import Album
+from .errors import *
+from .objects import Album
 
 class ApiAlbums:
     def __init__(self, client):
diff --git a/openphoto/api_photo.py b/openphoto/api_photo.py
index 221996c..033febc 100644
--- a/openphoto/api_photo.py
+++ b/openphoto/api_photo.py
@@ -1,7 +1,7 @@
 import base64
 
-from errors import *
-from objects import Photo
+from .errors import *
+from .objects import Photo
 
 class ApiPhotos:
     def __init__(self, client):
@@ -80,14 +80,16 @@ class ApiPhoto:
         return photo
 
     def upload(self, photo_file, **kwds):
-        result = self._client.post("/photo/upload.json",
-                                   files={'photo': open(photo_file, 'rb')},
-                                   **kwds)["result"]
+        with open(photo_file, 'rb') as f:
+            result = self._client.post("/photo/upload.json",
+                                       files={'photo': f},
+                                       **kwds)["result"]
         return Photo(self._client, result)
 
     def upload_encoded(self, photo_file, **kwds):
         """ Base64-encodes and uploads the specified file """
-        encoded_photo = base64.b64encode(open(photo_file, "rb").read())
+        with open(photo_file, "rb") as f:
+            encoded_photo = base64.b64encode(f.read())
         result = self._client.post("/photo/upload.json", photo=encoded_photo, 
                                    **kwds)["result"]
         return Photo(self._client, result)
diff --git a/openphoto/api_tag.py b/openphoto/api_tag.py
index bc87d32..be393c0 100644
--- a/openphoto/api_tag.py
+++ b/openphoto/api_tag.py
@@ -1,5 +1,5 @@
-from errors import *
-from objects import Tag
+from .errors import *
+from .objects import Tag
 
 class ApiTags:
     def __init__(self, client):
diff --git a/openphoto/main.py b/openphoto/main.py
index 920262e..a2f944b 100644
--- a/openphoto/main.py
+++ b/openphoto/main.py
@@ -2,7 +2,6 @@
 import os
 import sys
 import string
-import urllib
 from optparse import OptionParser
 
 try:
@@ -56,22 +55,22 @@ def main(args=sys.argv[1:]):
         try:
             client = OpenPhoto(config_file=options.config_file)
         except IOError as error:
-            print error
-            print
-            print "You must create a configuration file with the following contents:"
-            print "    host = your.host.com"
-            print "    consumerKey = your_consumer_key"
-            print "    consumerSecret = your_consumer_secret"
-            print "    token = your_access_token"
-            print "    tokenSecret = your_access_token_secret"
-            print
-            print "To get your credentials:"
-            print " * Log into your Trovebox site"
-            print " * Click the arrow on the top-right and select 'Settings'."
-            print " * Click the 'Create a new app' button."
-            print " * Click the 'View' link beside the newly created app."
-            print
-            print error
+            print(error)
+            print()
+            print("You must create a configuration file with the following contents:")
+            print("    host = your.host.com")
+            print("    consumerKey = your_consumer_key")
+            print("    consumerSecret = your_consumer_secret")
+            print("    token = your_access_token")
+            print("    tokenSecret = your_access_token_secret")
+            print()
+            print("To get your credentials:")
+            print(" * Log into your Trovebox site")
+            print(" * Click the arrow on the top-right and select 'Settings'.")
+            print(" * Click the 'Create a new app' button.")
+            print(" * Click the 'View' link beside the newly created app.")
+            print()
+            print(error)
             sys.exit(1)
 
     if options.method == "GET":
@@ -81,17 +80,17 @@ def main(args=sys.argv[1:]):
         result = client.post(options.endpoint, process_response=False, files=files, **params)
 
     if options.verbose:
-        print "==========\nMethod: %s\nHost: %s\nEndpoint: %s" % (options.method, config['host'], options.endpoint)
+        print("==========\nMethod: %s\nHost: %s\nEndpoint: %s" % (options.method, config['host'], options.endpoint))
         if len( params ) > 0:
-            print "Fields:"
-            for kv in params.iteritems():
-                print "  %s=%s" % kv
-        print "==========\n"
+            print("Fields:")
+            for kv in params.items():
+                print("  %s=%s" % kv)
+        print("==========\n")
 
     if options.pretty:
-        print json.dumps(json.loads(result), sort_keys=True, indent=4, separators=(',',':'))
+        print(json.dumps(json.loads(result), sort_keys=True, indent=4, separators=(',',':')))
     else:
-        print result
+        print(result)
 
 def extract_files(params):
     """
diff --git a/openphoto/objects.py b/openphoto/objects.py
index 155c711..f333847 100644
--- a/openphoto/objects.py
+++ b/openphoto/objects.py
@@ -1,5 +1,8 @@
-import urllib
-from errors import *
+try:
+	from urllib.parse import quote # Python3
+except ImportError:
+	from urllib import quote # Python2
+from .errors import *
 
 class OpenPhotoObject:
     """ Base object supporting the storage of custom fields as attributes """
@@ -128,13 +131,13 @@ class Tag(OpenPhotoObject):
         Returns True if successful.
         Raises an OpenPhotoError if not.
         """
-        result = self._openphoto.post("/tag/%s/delete.json" % urllib.quote(self.id), **kwds)["result"]
+        result = self._openphoto.post("/tag/%s/delete.json" % quote(self.id), **kwds)["result"]
         self._replace_fields({})
         return result
 
     def update(self, **kwds):
         """ Update this tag with the specified parameters """
-        new_dict = self._openphoto.post("/tag/%s/update.json" % urllib.quote(self.id), 
+        new_dict = self._openphoto.post("/tag/%s/update.json" % quote(self.id), 
                                         **kwds)["result"]
         self._replace_fields(new_dict)
 
diff --git a/openphoto/openphoto_http.py b/openphoto/openphoto_http.py
index 17919a2..7824bad 100644
--- a/openphoto/openphoto_http.py
+++ b/openphoto/openphoto_http.py
@@ -1,18 +1,36 @@
+from __future__ import unicode_literals
+import sys
 import os
-import urlparse
-import urllib
+try:
+    from urllib.parse import urlunparse # Python3
+except ImportError:
+    from urlparse import urlunparse # Python2
 import requests
 import requests_oauthlib
 import logging
-import StringIO
-import ConfigParser
 try:
-    import json
+    import io # Python3
 except ImportError:
-    import simplejson as json
+    import StringIO as io # Python2
+try:
+    from configparser import ConfigParser # Python3
+except ImportError:
+    from ConfigParser import SafeConfigParser as ConfigParser # Python2
 
-from objects import OpenPhotoObject
-from errors import *
+if sys.version < '3':
+    text_type = unicode # Python2
+else:
+    text_type = str # Python3
+
+from .objects import OpenPhotoObject
+from .errors import *
+
+if sys.version < '3':
+	# requests_oauth needs to decode to ascii for Python2
+    _oauth_decoding = "utf-8"
+else:
+	# requests_oauth needs to use (unicode) strings for Python3
+    _oauth_decoding = None # Python3
 
 DUPLICATE_RESPONSE = {"code": 409,
                       "message": "This photo already exists"}
@@ -75,15 +93,17 @@ class OpenPhotoHttp:
             endpoint = "/" + endpoint
         if self._api_version is not None:
             endpoint = "/v%d%s" % (self._api_version, endpoint)
-        url = urlparse.urlunparse(('http', self._host, endpoint, '', '', ''))
+        url = urlunparse(('http', self._host, endpoint, '', '', ''))
 
         if self._consumer_key:
             auth = requests_oauthlib.OAuth1(self._consumer_key, self._consumer_secret,
-                                             self._token, self._token_secret)
+                                            self._token, self._token_secret,
+                                            decoding=_oauth_decoding)
         else:
             auth = None
 
-        response = requests.get(url, params=params, auth=auth)
+        with requests.Session() as s:
+            response = s.get(url, params=params, auth=auth)
 
         self._logger.info("============================")
         self._logger.info("GET %s" % url)
@@ -115,20 +135,22 @@ class OpenPhotoHttp:
             endpoint = "/" + endpoint
         if self._api_version is not None:
             endpoint = "/v%d%s" % (self._api_version, endpoint)
-        url = urlparse.urlunparse(('http', self._host, endpoint, '', '', ''))
+        url = urlunparse(('http', self._host, endpoint, '', '', ''))
 
         if not self._consumer_key:
             raise OpenPhotoError("Cannot issue POST without OAuth tokens")
 
         auth = requests_oauthlib.OAuth1(self._consumer_key, self._consumer_secret,
-                                        self._token, self._token_secret)
-        if files:
-            # Need to pass parameters as URL query, so they get OAuth signed
-            response = requests.post(url, params=params, files=files, auth=auth)
-        else:
-            # Passing parameters as URL query doesn't work if there are no files to send.
-            # Send them as form data instead.
-            response = requests.post(url, data=params, auth=auth)
+                                        self._token, self._token_secret,
+                                        decoding=_oauth_decoding)
+        with requests.Session() as s:
+            if files:
+                # Need to pass parameters as URL query, so they get OAuth signed
+                response = s.post(url, params=params, files=files, auth=auth)
+            else:
+                # Passing parameters as URL query doesn't work if there are no files to send.
+                # Send them as form data instead.
+                response = s.post(url, data=params, auth=auth)
 
         self._logger.info("============================")
         self._logger.info("POST %s" % url)
@@ -156,9 +178,9 @@ class OpenPhotoHttp:
             if isinstance(value, OpenPhotoObject):
                 value = value.id
 
-            # Use UTF-8 encoding
-            if isinstance(value, unicode):
-                value = value.encode('utf-8')
+            # Ensure value is UTF-8 encoded
+            if isinstance(value, text_type):
+                value = value.encode("utf-8")
 
             # Handle lists
             if isinstance(value, list):
@@ -168,8 +190,8 @@ class OpenPhotoHttp:
                 for i, item in enumerate(new_list):
                     if isinstance(item, OpenPhotoObject):
                         new_list[i] = item.id
-                # Convert list to unicode string
-                value = u','.join([unicode(item) for item in new_list])
+                # Convert list to string
+                value = ','.join([str(item) for item in new_list])
 
             # Handle booleans
             if isinstance(value, bool):
@@ -188,7 +210,7 @@ class OpenPhotoHttp:
             json_response = response.json()
             code = json_response["code"]
             message = json_response["message"]
-        except ValueError, KeyError:
+        except (ValueError, KeyError):
             # Response wasn't OpenPhoto JSON - check the HTTP status code
             if 200 <= response.status_code < 300:
                 # Status code was valid, so just reraise the exception
@@ -236,14 +258,18 @@ class OpenPhotoHttp:
                     'token': '', 'tokenSecret':'',
                     }
         # Insert an section header at the start of the config file, so ConfigParser can understand it
-        buf = StringIO.StringIO()
+        buf = io.StringIO()
         buf.write('[%s]\n' % section)
-        buf.write(open(config_file).read())
+        with io.open(config_file, "r") as f:
+            buf.write(f.read())
 
         buf.seek(0, os.SEEK_SET)
-        parser = ConfigParser.SafeConfigParser()
+        parser = ConfigParser()
         parser.optionxform = str # Case-sensitive options
-        parser.readfp(buf)
+        try:
+            parser.read_file(buf) # Python3
+        except AttributeError:
+            parser.readfp(buf) # Python2
 
         # Trim quotes
         config = parser.items(section)
diff --git a/tests/test_albums.py b/tests/test_albums.py
index 0371bea..88eeb19 100644
--- a/tests/test_albums.py
+++ b/tests/test_albums.py
@@ -3,7 +3,7 @@ try:
 except ImportError:
     import unittest
 import openphoto
-import test_base
+from . import test_base
 
 class TestAlbums(test_base.TestBase):
     testcase_name = "album API"
diff --git a/tests/test_base.py b/tests/test_base.py
index ae5d350..86a27fe 100644
--- a/tests/test_base.py
+++ b/tests/test_base.py
@@ -1,3 +1,4 @@
+from __future__ import print_function
 import sys
 import os
 try:
@@ -35,9 +36,9 @@ class TestBase(unittest.TestCase):
         """ Ensure there is nothing on the server before running any tests """
         if cls.debug:
             if cls.api_version is None:
-                print "\nTesting Latest %s" % cls.testcase_name
+                print("\nTesting Latest %s" % cls.testcase_name)
             else:
-                print "\nTesting %s v%d" % (cls.testcase_name, cls.api_version)
+                print("\nTesting %s v%d" % (cls.testcase_name, cls.api_version))
 
         cls.client = openphoto.OpenPhoto(config_file=cls.config_file,
                                          api_version=cls.api_version)
@@ -71,9 +72,9 @@ class TestBase(unittest.TestCase):
         self.photos = self.client.photos.list()
         if len(self.photos) != 3:
             if self.debug:
-                print "[Regenerating Photos]"
+                print("[Regenerating Photos]")
             else:
-                print " ",
+                print(" ", end='')
                 sys.stdout.flush()
             if len(self.photos) > 0:
                 self._delete_all()
@@ -85,16 +86,16 @@ class TestBase(unittest.TestCase):
                 self.tags[0].id != self.TEST_TAG or
                 str(self.tags[0].count) != "3"):
             if self.debug:
-                print "[Regenerating Tags]"
+                print("[Regenerating Tags]")
             else:
-                print " ",
+                print(" ", end='')
                 sys.stdout.flush()
             self._delete_all()
             self._create_test_photos()
             self.photos = self.client.photos.list()
             self.tags = self.client.tags.list()
         if len(self.tags) != 1:
-            print "Tags: %s" % self.tags
+            print("Tags: %s" % self.tags)
             raise Exception("Tag creation failed")
 
         self.albums = self.client.albums.list()
@@ -102,9 +103,9 @@ class TestBase(unittest.TestCase):
                 self.albums[0].name != self.TEST_ALBUM or
                 self.albums[0].count != "3"):
             if self.debug:
-                print "[Regenerating Albums]"
+                print("[Regenerating Albums]")
             else:
-                print " ",
+                print(" ", end='')
                 sys.stdout.flush()
             self._delete_all()
             self._create_test_photos()
@@ -112,7 +113,7 @@ class TestBase(unittest.TestCase):
             self.tags = self.client.tags.list()
             self.albums = self.client.albums.list()
         if len(self.albums) != 1:
-            print "Albums: %s" % self.albums
+            print("Albums: %s" % self.albums)
             raise Exception("Album creation failed")
 
         logging.info("\nRunning %s..." % self.id())
diff --git a/tests/test_config.py b/tests/test_config.py
index de0b267..d0d21c2 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -27,13 +27,13 @@ class TestConfig(unittest.TestCase):
         shutil.rmtree(CONFIG_HOME_PATH, ignore_errors=True)
 
     def create_config(self, config_file, host):
-        f = open(os.path.join(CONFIG_PATH, config_file), "w")
-        f.write("host = %s\n" % host)
-        f.write("# Comment\n\n")
-        f.write("consumerKey = \"%s_consumer_key\"\n" % config_file)
-        f.write("\"consumerSecret\" = %s_consumer_secret\n" % config_file)
-        f.write("'token'=%s_token\n" % config_file)
-        f.write("tokenSecret = '%s_token_secret'\n" % config_file)
+        with open(os.path.join(CONFIG_PATH, config_file), "w") as f:
+            f.write("host = %s\n" % host)
+            f.write("# Comment\n\n")
+            f.write("consumerKey = \"%s_consumer_key\"\n" % config_file)
+            f.write("\"consumerSecret\" = %s_consumer_secret\n" % config_file)
+            f.write("'token'=%s_token\n" % config_file)
+            f.write("tokenSecret = '%s_token_secret'\n" % config_file)
 
     def test_default_config(self):
         """ Ensure the default config is loaded """
diff --git a/tests/test_framework.py b/tests/test_framework.py
index cd1700a..d011914 100644
--- a/tests/test_framework.py
+++ b/tests/test_framework.py
@@ -4,7 +4,7 @@ except ImportError:
     import unittest
 import logging
 import openphoto
-import test_base
+from . import test_base
 
 class TestFramework(test_base.TestBase):
     testcase_name = "framework"
diff --git a/tests/test_photos.py b/tests/test_photos.py
index dcd9c1e..0772d86 100644
--- a/tests/test_photos.py
+++ b/tests/test_photos.py
@@ -1,9 +1,10 @@
+from __future__ import unicode_literals
 try:
     import unittest2 as unittest
 except ImportError:
     import unittest
 import openphoto
-import test_base
+from . import test_base
 
 class TestPhotos(test_base.TestBase):
     testcase_name = "photo API"
@@ -72,7 +73,7 @@ class TestPhotos(test_base.TestBase):
 
     def test_update(self):
         """ Update a photo by editing the title """
-        title = u"\xfcmlaut" # umlauted umlaut
+        title = "\xfcmlaut" # umlauted umlaut
         # Get a photo and check that it doesn't have the magic title
         photo = self.photos[0]
         self.assertNotEqual(photo.title, title)
diff --git a/tests/test_tags.py b/tests/test_tags.py
index 143742e..a46f1cc 100644
--- a/tests/test_tags.py
+++ b/tests/test_tags.py
@@ -3,7 +3,7 @@ try:
 except ImportError:
     import unittest
 import openphoto
-import test_base
+from . import test_base
 
 @unittest.skipIf(test_base.get_test_server_api() == 1,
                  "The tag API didn't work at v1 - see frontend issue #927")
diff --git a/tox.ini b/tox.ini
index 23a69ed..7f1f87f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,10 @@
 [tox]
-envlist = py27,py26
+envlist = py26, py27, py33
 
 [testenv]
+commands = python -m unittest discover --catch
+
+[testenv:py26]
 commands = unit2 discover --catch
 deps =
     unittest2