diff --git a/installinstallmacos.py b/installinstallmacos.py
index 2c9be28..d9ffe5f 100755
--- a/installinstallmacos.py
+++ b/installinstallmacos.py
@@ -23,6 +23,9 @@ A tool to download the parts for an Install macOS app from Apple's
 softwareupdate servers and install a functioning Install macOS app onto an
 empty disk image'''
 
+# Python 3 compatibility shims
+from __future__ import (
+    absolute_import, division, print_function, unicode_literals)
 
 import argparse
 import gzip
@@ -30,8 +33,13 @@ import os
 import plistlib
 import subprocess
 import sys
-import urlparse
 import xattr
+try:
+    # python 2
+    from urllib.parse import urlsplit
+except ImportError:
+    # python 3
+    from urlparse import urlsplit
 from xml.dom import minidom
 from xml.parsers.expat import ExpatError
 from distutils.version import LooseVersion
@@ -109,10 +117,38 @@ def get_current_build_info():
     return build_info
 
 
+def get_input(prompt=None):
+    '''Python 2 and 3 wrapper for raw_input/input'''
+    try:
+        return raw_input(prompt)
+    except NameError:
+        # raw_input doesn't exist in Python 3
+        return input(prompt)
+
+
+def read_plist(filepath):
+    '''Wrapper for the differences between Python 2 and Python 3's plistlib'''
+    try:
+        with open(filepath, "rb") as fileobj:
+            return plistlib.load(fileobj)
+    except AttributeError:
+        # plistlib module doesn't have a load function (as in Python 2)
+        return plistlib.readPlist(filepath)
+
+
+def read_plist_from_string(bytestring):
+    '''Wrapper for the differences between Python 2 and Python 3's plistlib'''
+    try:
+        return plistlib.loads(bytestring)
+    except AttributeError:
+        # plistlib module doesn't have a load function (as in Python 2)
+        return plistlib.readPlistFromString(bytestring)
+
+
 def get_seeding_program(sucatalog_url):
     '''Returns a seeding program name based on the sucatalog_url'''
     try:
-        seed_catalogs = plistlib.readPlist(SEED_CATALOGS_PLIST)
+        seed_catalogs = read_plist(SEED_CATALOGS_PLIST)
         for key, value in seed_catalogs.items():
             if sucatalog_url == value:
                 return key
@@ -124,7 +160,7 @@ def get_seeding_program(sucatalog_url):
 def get_seed_catalog(seedname='DeveloperSeed'):
     '''Returns the developer seed sucatalog'''
     try:
-        seed_catalogs = plistlib.readPlist(SEED_CATALOGS_PLIST)
+        seed_catalogs = read_plist(SEED_CATALOGS_PLIST)
         return seed_catalogs.get(seedname)
     except (OSError, ExpatError, AttributeError, KeyError):
         return ''
@@ -133,8 +169,8 @@ def get_seed_catalog(seedname='DeveloperSeed'):
 def get_seeding_programs():
     '''Returns the list of seeding program names'''
     try:
-        seed_catalogs = plistlib.readPlist(SEED_CATALOGS_PLIST)
-        return seed_catalogs.keys()
+        seed_catalogs = read_plist(SEED_CATALOGS_PLIST)
+        return list(seed_catalogs.keys())
     except (OSError, ExpatError, AttributeError, KeyError):
         return ''
 
@@ -151,17 +187,17 @@ def make_sparse_image(volume_name, output_path):
            '-volname', volume_name, '-type', 'SPARSE', '-plist', output_path]
     try:
         output = subprocess.check_output(cmd)
-    except subprocess.CalledProcessError, err:
-        print >> sys.stderr, err
+    except subprocess.CalledProcessError as err:
+        print(err, file=sys.stderr)
         exit(-1)
     try:
-        return plistlib.readPlistFromString(output)[0]
-    except IndexError, err:
-        print >> sys.stderr, 'Unexpected output from hdiutil: %s' % output
+        return read_plist_from_string(output)[0]
+    except IndexError as err:
+        print('Unexpected output from hdiutil: %s' % output, file=sys.stderr)
         exit(-1)
-    except ExpatError, err:
-        print >> sys.stderr, 'Malformed output from hdiutil: %s' % output
-        print >> sys.stderr, err
+    except ExpatError as err:
+        print('Malformed output from hdiutil: %s' % output, file=sys.stderr)
+        print(err, file=sys.stderr)
         exit(-1)
 
 
@@ -169,16 +205,16 @@ def make_compressed_dmg(app_path, diskimagepath, volume_name):
     """Returns path to newly-created compressed r/o disk image containing
     Install macOS.app"""
 
-    print ('Making read-only compressed disk image containing %s...'
-           % os.path.basename(app_path))
-    cmd = ['/usr/bin/hdiutil', 'create', '-volname', volume_name, '-fs', 'HFS+',
+    print('Making read-only compressed disk image containing %s...'
+          % os.path.basename(app_path))
+    cmd = ['/usr/bin/hdiutil', 'create', '-fs', 'HFS+',
            '-srcfolder', app_path, diskimagepath]
     try:
         subprocess.check_call(cmd)
-    except subprocess.CalledProcessError, err:
-        print >> sys.stderr, err
+    except subprocess.CalledProcessError as err:
+        print(err, file=sys.stderr)
     else:
-        print 'Disk image created at: %s' % diskimagepath
+        print('Disk image created at: %s' % diskimagepath)
 
 
 def mountdmg(dmgpath):
@@ -194,10 +230,11 @@ def mountdmg(dmgpath):
                             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     (pliststr, err) = proc.communicate()
     if proc.returncode:
-        print >> sys.stderr, 'Error: "%s" while mounting %s.' % (err, dmgname)
+        print('Error: "%s" while mounting %s.' % (err, dmgname),
+              file=sys.stderr)
         return None
     if pliststr:
-        plist = plistlib.readPlistFromString(pliststr)
+        plist = read_plist_from_string(pliststr)
         for entity in plist['system-entities']:
             if 'mount-point' in entity:
                 mountpoints.append(entity['mount-point'])
@@ -214,13 +251,13 @@ def unmountdmg(mountpoint):
                             stderr=subprocess.PIPE)
     (dummy_output, err) = proc.communicate()
     if proc.returncode:
-        print >> sys.stderr, 'Polite unmount failed: %s' % err
-        print >> sys.stderr, 'Attempting to force unmount %s' % mountpoint
+        print('Polite unmount failed: %s' % err, file=sys.stderr)
+        print('Attempting to force unmount %s' % mountpoint, file=sys.stderr)
         # try forcing the unmount
         retcode = subprocess.call(['/usr/bin/hdiutil', 'detach', mountpoint,
                                    '-force'])
         if retcode:
-            print >> sys.stderr, 'Failed to unmount %s' % mountpoint
+            print('Failed to unmount %s' % mountpoint, file=sys.stderr)
 
 
 def install_product(dist_path, target_vol):
@@ -230,8 +267,8 @@ def install_product(dist_path, target_vol):
     try:
         subprocess.check_call(cmd)
         return True
-    except subprocess.CalledProcessError, err:
-        print >> sys.stderr, err
+    except subprocess.CalledProcessError as err:
+        print(err, file=sys.stderr)
         return False
 
 
@@ -248,7 +285,7 @@ def replicate_url(full_url,
     '''Downloads a URL and stores it in the same relative path on our
     filesystem. Returns a path to the replicated file.'''
 
-    path = urlparse.urlsplit(full_url)[2]
+    path = urlsplit(full_url)[2]
     relative_url = path.lstrip('/')
     relative_url = os.path.normpath(relative_url)
     local_file_path = os.path.join(root_dir, relative_url)
@@ -263,10 +300,10 @@ def replicate_url(full_url,
         if attempt_resume:
             curl_cmd.extend(['-C', '-'])
     curl_cmd.append(full_url)
-    # print "Downloading %s..." % full_url
+    # print("Downloading %s..." % full_url)
     try:
         subprocess.check_call(curl_cmd)
-    except subprocess.CalledProcessError, err:
+    except subprocess.CalledProcessError as err:
         raise ReplicationError(err)
     return local_file_path
 
@@ -278,9 +315,9 @@ def parse_server_metadata(filename):
     title = ''
     vers = ''
     try:
-        md_plist = plistlib.readPlist(filename)
-    except (OSError, IOError, ExpatError), err:
-        print >> sys.stderr, 'Error reading %s: %s' % (filename, err)
+        md_plist = read_plist(filename)
+    except (OSError, IOError, ExpatError) as err:
+        print('Error reading %s: %s' % (filename, err), file=sys.stderr)
         return {}
     vers = md_plist.get('CFBundleShortVersionString', '')
     localization = md_plist.get('localization', {})
@@ -303,12 +340,11 @@ def get_server_metadata(catalog, product_key, workdir, ignore_cache=False):
             smd_path = replicate_url(
                 url, root_dir=workdir, ignore_cache=ignore_cache)
             return smd_path
-        except ReplicationError, err:
-            print >> sys.stderr, (
-                'Could not replicate %s: %s' % (url, err))
+        except ReplicationError as err:
+            print('Could not replicate %s: %s' % (url, err), file=sys.stderr)
             return None
     except KeyError:
-        print >> sys.stderr, 'Malformed catalog.'
+        print('Malformed catalog.', file=sys.stderr)
         return None
 
 
@@ -319,10 +355,10 @@ def parse_dist(filename):
     try:
         dom = minidom.parse(filename)
     except ExpatError:
-        print >> sys.stderr, 'Invalid XML in %s' % filename
+        print('Invalid XML in %s' % filename, file=sys.stderr)
         return dist_info
-    except IOError, err:
-        print >> sys.stderr, 'Error reading %s: %s' % (filename, err)
+    except IOError as err:
+        print('Error reading %s: %s' % (filename, err), file=sys.stderr)
         return dist_info
 
     auxinfos = dom.getElementsByTagName('auxinfo')
@@ -380,26 +416,26 @@ def download_and_parse_sucatalog(sucatalog, workdir, ignore_cache=False):
     try:
         localcatalogpath = replicate_url(
             sucatalog, root_dir=workdir, ignore_cache=ignore_cache)
-    except ReplicationError, err:
-        print >> sys.stderr, 'Could not replicate %s: %s' % (sucatalog, err)
+    except ReplicationError as err:
+        print('Could not replicate %s: %s' % (sucatalog, err), file=sys.stderr)
         exit(-1)
     if os.path.splitext(localcatalogpath)[1] == '.gz':
         with gzip.open(localcatalogpath) as the_file:
             content = the_file.read()
             try:
-                catalog = plistlib.readPlistFromString(content)
+                catalog = read_plist_from_string(content)
                 return catalog
-            except ExpatError, err:
-                print >> sys.stderr, (
-                    'Error reading %s: %s' % (localcatalogpath, err))
+            except ExpatError as err:
+                print('Error reading %s: %s' % (localcatalogpath, err),
+                      file=sys.stderr)
                 exit(-1)
     else:
         try:
-            catalog = plistlib.readPlist(localcatalogpath)
+            catalog = read_plist(localcatalogpath)
             return catalog
-        except (OSError, IOError, ExpatError), err:
-            print >> sys.stderr, (
-                'Error reading %s: %s' % (localcatalogpath, err))
+        except (OSError, IOError, ExpatError) as err:
+            print('Error reading %s: %s' % (localcatalogpath, err),
+                  file=sys.stderr)
             exit(-1)
 
 
@@ -408,8 +444,7 @@ def find_mac_os_installers(catalog):
     installers'''
     mac_os_installer_products = []
     if 'Products' in catalog:
-        product_keys = list(catalog['Products'].keys())
-        for product_key in product_keys:
+        for product_key in catalog['Products'].keys():
             product = catalog['Products'][product_key]
             try:
                 if product['ExtendedMetaInfo'][
@@ -436,16 +471,17 @@ def os_installer_product_info(catalog, workdir, ignore_cache=False):
         try:
             dist_path = replicate_url(
                 dist_url, root_dir=workdir, ignore_cache=ignore_cache)
-        except ReplicationError, err:
-            print >> sys.stderr, 'Could not replicate %s: %s' % (dist_url, err)
-        dist_info = parse_dist(dist_path)
-        product_info[product_key]['DistributionPath'] = dist_path
-        unsupported_models = get_unsupported_models(dist_path)
-        product_info[product_key]['UnsupportedModels'] = unsupported_models
-        board_ids = get_board_ids(dist_path)
-        product_info[product_key]['BoardIDs'] = board_ids
-        product_info[product_key].update(dist_info)
-
+        except ReplicationError as err:
+            print('Could not replicate %s: %s' % (dist_url, err),
+                  file=sys.stderr)
+        else:
+            dist_info = parse_dist(dist_path)
+            product_info[product_key]['DistributionPath'] = dist_path
+            unsupported_models = get_unsupported_models(dist_path)
+            product_info[product_key]['UnsupportedModels'] = unsupported_models
+            board_ids = get_board_ids(dist_path)
+            product_info[product_key]['BoardIDs'] = board_ids
+            product_info[product_key].update(dist_info)
     return product_info
 
 
@@ -470,18 +506,17 @@ def replicate_product(catalog, product_id, workdir, ignore_cache=False):
                     package['URL'], root_dir=workdir,
                     show_progress=True, ignore_cache=ignore_cache,
                     attempt_resume=(not ignore_cache))
-            except ReplicationError, err:
-                print >> sys.stderr, (
-                    'Could not replicate %s: %s' % (package['URL'], err))
+            except ReplicationError as err:
+                print('Could not replicate %s: %s' % (package['URL'], err),
+                      file=sys.stderr)
                 exit(-1)
         if 'MetadataURL' in package:
             try:
                 replicate_url(package['MetadataURL'], root_dir=workdir,
                               ignore_cache=ignore_cache)
-            except ReplicationError, err:
-                print >> sys.stderr, (
-                    'Could not replicate %s: %s'
-                    % (package['MetadataURL'], err))
+            except ReplicationError as err:
+                print('Could not replicate %s: %s'
+                      % (package['MetadataURL'], err), file=sys.stderr)
                 exit(-1)
 
 
@@ -561,31 +596,29 @@ def main():
     build_info = get_current_build_info()
     is_vm = is_a_vm()
 
-    print "This Mac:"
+    print('This Mac:')
     if is_vm == True:
-        print "Identified as a Virtual Machine"
-    print "%-17s: %s" % ('Model Identifier', hw_model)
-    print "%-17s: %s" % ('Board ID', board_id)
-    print "%-17s: %s" % ('OS Version', build_info[0])
-    print "%-17s: %s\n" % ('Build ID', build_info[1])
+        print('Identified as a Virtual Machine')
+    print('%-17s: %s' % ('Model Identifier', hw_model))
+    print('%-17s: %s' % ('Board ID', board_id))
+    print('%-17s: %s' % ('OS Version', build_info[0]))
+    print('%-17s: %s\n' % ('Build ID', build_info[1]))
 
     if args.catalogurl:
         su_catalog_url = args.catalogurl
     elif args.seedprogram:
         su_catalog_url = get_seed_catalog(args.seedprogram)
         if not su_catalog_url:
-            print >> sys.stderr, (
-                'Could not find a catalog url for seed program %s'
-                % args.seedprogram)
-            print >> sys.stderr, (
-                'Valid seeding programs are: %s'
-                % ', '.join(get_seeding_programs()))
+            print('Could not find a catalog url for seed program %s'
+                  % args.seedprogram, file=sys.stderr)
+            print('Valid seeding programs are: %s'
+                  % ', '.join(get_seeding_programs()), file=sys.stderr)
             exit(-1)
     else:
         su_catalog_url = get_default_catalog()
         if not su_catalog_url:
-            print >> sys.stderr, (
-                'Could not find a default catalog url for this OS version.')
+            print('Could not find a default catalog url for this OS version.',
+                  file=sys.stderr)
             exit(-1)
 
     # download sucatalog and look for products that are for macOS installers
@@ -595,8 +628,8 @@ def main():
         catalog, args.workdir, ignore_cache=args.ignore_cache)
 
     if not product_info:
-        print >> sys.stderr, (
-            'No macOS installer products found in the sucatalog.')
+        print('No macOS installer products found in the sucatalog.',
+              file=sys.stderr)
         exit(-1)
 
     output_plist = "%s/softwareupdate.plist" % args.workdir
@@ -606,8 +639,8 @@ def main():
     valid_build_found = False
 
     # display a menu of choices (some seed catalogs have multiple installers)
-    print '%2s  %-15s %-10s %-8s %-11s %-30s %s' % ('#', 'ProductID', 'Version',
-                                     'Build', 'Post Date', 'Title', 'Notes')
+    print('%2s  %-15s %-10s %-8s %-11s %-30s %s' % ('#', 'ProductID', 'Version',
+                                     'Build', 'Post Date', 'Title', 'Notes'))
     for index, product_id in enumerate(product_info):
         not_valid = ''
         if hw_model in product_info[product_id]['UnsupportedModels'] and is_vm == False:
@@ -619,7 +652,7 @@ def main():
         else:
             valid_build_found = True
 
-        print '%2s  %-15s %-10s %-8s %-11s %-30s %s' % (
+        print('%2s  %-15s %-10s %-8s %-11s %-30s %s' % (
             index + 1,
             product_id,
             product_info[product_id]['version'],
@@ -627,7 +660,7 @@ def main():
             product_info[product_id]['PostDate'].strftime('%Y-%m-%d'),
             product_info[product_id]['title'],
             not_valid
-        )
+        ))
 
         # go through various options for automatically determining the answer:
 
@@ -648,7 +681,7 @@ def main():
                 continue
 
         # determine the lowest valid build ID and select this
-        # when using auto and version options
+        # when using auto and version options
         if (args.auto or args.version or args.os) and 'Beta' not in product_info[product_id]['title']:
             try:
                 lowest_valid_build
@@ -685,13 +718,13 @@ def main():
 
     # Stop here if no valid builds found
     if valid_build_found == False:
-        print 'No valid build found for this hardware'
+        print('No valid build found for this hardware')
         exit(0)
 
     # Output a plist of available updates and quit if list option chosen
     if args.list:
         plistlib.writePlist(pl, output_plist)
-        print ('\n'
+        print('\n'
                'Valid seeding programs are: %s'
                % ', '.join(get_seeding_programs()))
         exit(0)
@@ -701,35 +734,41 @@ def main():
         try:
             answer
         except NameError:
-            print ('\n'
+            print('\n'
                    'Build %s is not available. '
                    'Run again without --build argument '
                    'to select a valid build to download.\n' % args.build)
             exit(0)
         else:
-            print '\nBuild %s available. Downloading #%s...\n' % (args.build, answer)
+            print('\n'
+                  'Build %s available. Downloading #%s...\n'
+                  % (args.build, answer))
     elif args.current:
         try:
             answer
         except NameError:
-            print ('\n'
+            print('\n'
                    'Build %s is not available. '
                    'Run again without --current argument '
                    'to select a valid build to download.\n' % build_info[0])
             exit(0)
         else:
-            print '\nBuild %s available. Downloading #%s...\n' % (build_info[0], answer)
+            print('\n'
+                  'Build %s available. Downloading #%s...\n'
+                  % (build_info[0], answer))
     elif args.version:
         try:
             answer
         except NameError:
-            print ('\n'
+            print('\n'
                    'Item # %s is not available. '
                    'Run again without --version argument '
                    'to select a valid build to download.\n' % args.version)
             exit(0)
         else:
-            print '\nBuild %s selected. Downloading #%s...\n' % (lowest_valid_build, answer)
+            print('\n'
+                  'Build %s selected. Downloading #%s...\n'
+                  % (lowest_valid_build, answer))
     elif args.os:
         try:
             answer
@@ -740,30 +779,34 @@ def main():
                    'to select a valid build to download.\n' % args.os)
             exit(0)
         else:
-            print '\nBuild %s selected. Downloading #%s...\n' % (lowest_valid_build, answer)
+            print('\n'
+                  'Build %s selected. Downloading #%s...\n'
+                  % (lowest_valid_build, answer))
     elif args.auto:
         try:
             answer
         except NameError:
-            print ('\n'
+            print('\n'
                    'No valid version available. '
                    'Run again without --auto argument '
                    'to select a valid build to download.\n')
             exit(0)
         else:
-            print '\nBuild %s selected. Downloading #%s...\n' % (lowest_valid_build, answer)
+            print('\n'
+                  'Build %s selected. Downloading #%s...\n'
+                  % (lowest_valid_build, answer))
     else:
-        # default option to interactively offer selection
-        answer = raw_input(
+        # default option to interactively offer selection
+        answer = get_input(
                 '\nChoose a product to download (1-%s): ' % len(product_info))
 
     try:
         index = int(answer) - 1
         if index < 0:
             raise ValueError
-        product_id = product_info.keys()[index]
+        product_id = list(product_info.keys())[index]
     except (ValueError, IndexError):
-        print 'Exiting.'
+        print('Exiting.')
         exit(0)
 
     # download all the packages for the selected product
@@ -779,7 +822,7 @@ def main():
         os.unlink(sparse_diskimage_path)
 
     # make an empty sparseimage and mount it
-    print 'Making empty sparseimage...'
+    print('Making empty sparseimage...')
     sparse_diskimage_path = make_sparse_image(volname, sparse_diskimage_path)
     mountpoint = mountdmg(sparse_diskimage_path)
     if mountpoint:
@@ -788,16 +831,18 @@ def main():
             product_info[product_id]['DistributionPath'],
             mountpoint)
         if not success:
-            print >> sys.stderr, 'Product installation failed.'
+            print('Product installation failed.', file=sys.stderr)
             unmountdmg(mountpoint)
             exit(-1)
         # add the seeding program xattr to the app if applicable
-        seeding_program = get_seeding_program(args.catalogurl)
+        seeding_program = get_seeding_program(su_catalog_url)
         if seeding_program:
             installer_app = find_installer_app(mountpoint)
             if installer_app:
+                print("Adding seeding program %s extended attribute to app"
+                      % seeding_program)
                 xattr.setxattr(installer_app, 'SeedProgram', seeding_program)
-        print 'Product downloaded and installed to %s' % sparse_diskimage_path
+        print('Product downloaded and installed to %s' % sparse_diskimage_path)
         if args.raw:
             unmountdmg(mountpoint)
         else: