diff --git a/build_library/disk_util b/build_library/disk_util
index 267ebb32ac..8505c0db77 100755
--- a/build_library/disk_util
+++ b/build_library/disk_util
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 # Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
@@ -66,9 +66,9 @@ def LoadPartitionConfig(options):
     raise InvalidLayout('Metadata is missing required entries: %s' % e)
 
   def VerifyLayout(layout_name, layout, base=None):
-    for part_num, part in layout.iteritems():
+    for part_num, part in layout.items():
       part['num'] = int(part_num)
-      part_keys = set(part.iterkeys())
+      part_keys = set(part.keys())
       unknown_keys = part_keys - valid_layout_keys
       if unknown_keys:
         raise InvalidLayout('Unknown items in partition %s %s: %r' %
@@ -79,7 +79,7 @@ def LoadPartitionConfig(options):
 
       if base:
         part_base = base.get(part_num, {})
-        part_keys.update(part_base.iterkeys())
+        part_keys.update(iter(part_base.keys()))
 
       if part.get('type', None) == 'blank':
         continue
@@ -122,12 +122,12 @@ def LoadPartitionConfig(options):
     # Fill in default values from base,
     # dict doesn't have a update()+setdefault() method so this looks tedious
     if base:
-      for part_num, base_part in base.iteritems():
+      for part_num, base_part in base.items():
         part = layout.setdefault(part_num, {})
-        for base_key, base_value in base_part.iteritems():
+        for base_key, base_value in base_part.items():
           part.setdefault(base_key, base_value)
 
-    for part_num, part in sorted(layout.iteritems(), key=lambda t: int(t[0])):
+    for part_num, part in sorted(iter(layout.items()), key=lambda t: int(t[0])):
       if part['type'] == 'blank':
         continue
 
@@ -163,7 +163,7 @@ def LoadPartitionConfig(options):
   # Verify 'base' before other layouts because it is inherited by the others
   # Fill in extra/default values in base last so they aren't inherited
   VerifyLayout('base', base)
-  for layout_name, layout in config['layouts'].iteritems():
+  for layout_name, layout in config['layouts'].items():
     if layout_name == 'base':
       continue
     VerifyLayout(layout_name, layout, base)
@@ -225,7 +225,7 @@ def GetPartitionTableFromImage(options, config, partitions):
     else:
       part['image_compat'] = False
 
-  for part in partitions.itervalues():
+  for part in partitions.values():
     if part.get('type', 'blank') == 'blank':
       continue
     if not part.get('image_exists', False):
@@ -240,7 +240,7 @@ def GetPartitionTableFromImage(options, config, partitions):
         part['image_fs_type'] = None
 
   # Set compat flags for any partition not in the image
-  for part in partitions.itervalues():
+  for part in partitions.values():
     part.setdefault('image_exists', False)
     if part.get('type', 'blank') == 'blank':
       part.setdefault('image_compat', True)
@@ -269,7 +269,7 @@ def WritePartitionTable(options, config=None, partitions=None):
   else:
     # If we are not creating a fresh image all partitions must be compatible.
     GetPartitionTableFromImage(options, config, partitions)
-    if not all(p['image_compat'] for p in partitions.itervalues()):
+    if not all(p['image_compat'] for p in partitions.values()):
       raise InvalidLayout("New disk layout is incompatible existing image")
 
     # Extend the disk image size as needed
@@ -279,7 +279,7 @@ def WritePartitionTable(options, config=None, partitions=None):
 
   hybrid = None
   prioritize = []
-  for partition in partitions.itervalues():
+  for partition in partitions.values():
     if partition['type'] != 'blank':
       Cgpt('add', '-i', partition['num'],
                   '-b', partition['first_block'],
@@ -469,8 +469,8 @@ def PartitionLoop(options, partition):
 
 
 def FormatPartition(options, part):
-  print "Formatting partition %s (%s) as %s" % (
-          part['num'], part['label'], part['fs_type'])
+  print("Formatting partition %s (%s) as %s" % (
+          part['num'], part['label'], part['fs_type']))
 
   with PartitionLoop(options, part) as loop_dev:
     if part['fs_type'] in ('ext2', 'ext4'):
@@ -497,7 +497,7 @@ def Format(options):
   config, partitions = LoadPartitionConfig(options)
   WritePartitionTable(options, config, partitions)
 
-  for part in partitions.itervalues():
+  for part in partitions.values():
     if part['type'] == 'blank' or 'fs_type' not in part:
       continue
 
@@ -542,13 +542,13 @@ def Update(options):
   config, partitions = LoadPartitionConfig(options)
   WritePartitionTable(options, config, partitions)
 
-  for part in partitions.itervalues():
+  for part in partitions.values():
     if not part.get('fs_type', None):
       continue
     elif not part['image_fs_type']:
       FormatPartition(options, part)
 
-  for part in partitions.itervalues():
+  for part in partitions.values():
     resize_func = None
     if not part.get('fs_type', None):
       continue
@@ -561,8 +561,8 @@ def Update(options):
     else:
       continue
 
-    print "Resizing partition %s (%s) to %s bytes" % (
-            part['num'], part['label'], part['fs_bytes'])
+    print("Resizing partition %s (%s) to %s bytes" % (
+            part['num'], part['label'], part['fs_bytes']))
 
     with PartitionLoop(options, part) as loop_dev:
       resize_func(part, loop_dev)
@@ -582,7 +582,7 @@ def Mount(options):
   GetPartitionTableFromImage(options, config, partitions)
   mounts = {}
 
-  for part_num, part in partitions.iteritems():
+  for part_num, part in partitions.items():
     path = part.get('mount', None)
     if not path or not path.startswith('/'):
       continue
@@ -625,7 +625,7 @@ def Mount(options):
     if err is not None:
       raise err
 
-    for src, dst in mount.get('binds', {}).iteritems():
+    for src, dst in mount.get('binds', {}).items():
       # src may be relative or absolute, os.path.join handles this.
       full_src =  os.path.realpath(
               options.mount_dir + os.path.join(mount['mount'], src))
@@ -650,11 +650,11 @@ def ReadWriteSubvol(options, partition, disable_rw):
   """
 
   if disable_rw:
-    print "Disabling read-write on default subvolume of partition %s (%s)" % (
-            partition['num'], partition['label'])
+    print("Disabling read-write on default subvolume of partition %s (%s)" % (
+            partition['num'], partition['label']))
   else:
-    print "Enabling read-write on default subvolume of partition %s (%s)" % (
-            partition['num'], partition['label'])
+    print("Enabling read-write on default subvolume of partition %s (%s)" % (
+            partition['num'], partition['label']))
 
   with PartitionLoop(options, partition) as loop_dev:
     btrfs_mount = tempfile.mkdtemp()
@@ -701,11 +701,11 @@ def Tune2fsReadWrite(options, partition, disable_rw):
   """
 
   if disable_rw:
-    print "Disabling read-write mounting of partition %s (%s)" % (
-            partition['num'], partition['label'])
+    print("Disabling read-write mounting of partition %s (%s)" % (
+            partition['num'], partition['label']))
   else:
-    print "Enabling read-write mounting of partition %s (%s)" % (
-            partition['num'], partition['label'])
+    print("Enabling read-write mounting of partition %s (%s)" % (
+            partition['num'], partition['label']))
 
   # offset of ro_compat, highest order byte (le 32 bit field)
   flag_offset = 0x464 + 3
@@ -767,7 +767,7 @@ def Verity(options):
   config, partitions = LoadPartitionConfig(options)
   GetPartitionTableFromImage(options, config, partitions)
 
-  for part_num, part in partitions.iteritems():
+  for part_num, part in partitions.items():
     if 'verity' not in part.get('features', []):
       continue
 
@@ -848,7 +848,7 @@ def GetPartitionByLabel(partitions, label):
   Returns:
     An object for the selected partition
   """
-  for partition in partitions.itervalues():
+  for partition in partitions.values():
     if partition['type'] == 'blank':
       continue
     elif partition['label'] == label:
@@ -882,7 +882,7 @@ def GetBlockSize(options):
   """
 
   config, partitions = LoadPartitionConfig(options)
-  print config['metadata']['block_size']
+  print(config['metadata']['block_size'])
 
 
 def GetFilesystemBlockSize(options):
@@ -897,7 +897,7 @@ def GetFilesystemBlockSize(options):
   """
 
   config, partitions = LoadPartitionConfig(options)
-  print config['metadata']['fs_block_size']
+  print(config['metadata']['fs_block_size'])
 
 
 def GetPartitionSize(options):
@@ -911,7 +911,7 @@ def GetPartitionSize(options):
 
   partitions = GetPartitionTableFromConfig(options)
   partition = GetPartitionByNumber(partitions, options.partition_num)
-  print partition['bytes']
+  print(partition['bytes'])
 
 
 def GetFilesystemSize(options):
@@ -927,7 +927,7 @@ def GetFilesystemSize(options):
 
   partitions = GetPartitionTableFromConfig(options)
   partition = GetPartitionByNumber(partitions, options.partition_num)
-  print partition.get('fs_bytes', partition['bytes'])
+  print(partition.get('fs_bytes', partition['bytes']))
 
 
 def GetLabel(options):
@@ -941,7 +941,7 @@ def GetLabel(options):
 
   partitions = GetPartitionTableFromConfig(options)
   partition = GetPartitionByNumber(partitions, options.partition_num)
-  print partition.get('label', 'UNTITLED')
+  print(partition.get('label', 'UNTITLED'))
 
 
 def GetNum(options):
@@ -955,7 +955,7 @@ def GetNum(options):
 
   partitions = GetPartitionTableFromConfig(options)
   partition = GetPartitionByLabel(partitions, options.label)
-  print partition.get('num', '-1')
+  print(partition.get('num', '-1'))
 
 
 def GetUuid(options):
@@ -969,7 +969,7 @@ def GetUuid(options):
 
   partitions = GetPartitionTableFromConfig(options)
   partition = GetPartitionByLabel(partitions, options.label)
-  print partition.get('uuid', '')
+  print(partition.get('uuid', ''))
 
 
 def DoDebugOutput(options):
@@ -983,7 +983,7 @@ def DoDebugOutput(options):
   """
   partitions = GetPartitionTableFromConfig(options)
 
-  for num, partition in sorted(partitions.iteritems()):
+  for num, partition in sorted(partitions.items()):
     if partition['type'] != 'blank':
       if partition['bytes'] < 1024 * 1024:
         size = '%d bytes' % partition['bytes']
@@ -994,11 +994,11 @@ def DoDebugOutput(options):
           fs_size = '%d bytes' % partition['fs_bytes']
         else:
           fs_size = '%d MB' % (partition['fs_bytes'] / 1024 / 1024)
-        print '%s: %s - %s/%s' % (num, partition['label'], fs_size, size)
+        print('%s: %s - %s/%s' % (num, partition['label'], fs_size, size))
       else:
-        print '%s: %s - %s' % (num, partition['label'], size)
+        print('%s: %s - %s' % (num, partition['label'], size))
     else:
-      print '%s: blank' % num
+      print('%s: blank' % num)
 
 
 def DoParseOnly(options):
diff --git a/build_library/gen_tmpfiles.py b/build_library/gen_tmpfiles.py
index c0133f6dbd..a4b4134ba1 100755
--- a/build_library/gen_tmpfiles.py
+++ b/build_library/gen_tmpfiles.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 '''Scan an existing directory tree and record installed directories.
 
 During build a number of directories under /var are created in the state
@@ -82,7 +82,7 @@ def main():
         fd.write('\n'.join(config)+'\n')
         fd.close()
     else:
-        print '\n'.join(config)
+        print('\n'.join(config))
 
 if __name__ == '__main__':
     main()
diff --git a/build_library/generate_au_zip.py b/build_library/generate_au_zip.py
index 6db1a1bae3..437ccce112 100755
--- a/build_library/generate_au_zip.py
+++ b/build_library/generate_au_zip.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 # Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
@@ -120,7 +120,7 @@ def DepsToCopy(ldd_files, allow_list):
       proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE)
       (stdout_data, stderr_data) = proc.communicate(input=None)
-    except subprocess.CalledProcessError, e:
+    except subprocess.CalledProcessError as e:
       logging.error('Command %s failed', cmd)
       logging.error('error code %s', e.returncode)
       logging.error('ouput %s', e.output)
@@ -153,7 +153,7 @@ def CopyRequiredFiles(dest_files_root, allow_list):
     sys.exit(1)
 
   all_files = DYNAMIC_EXECUTABLES + STATIC_FILES
-  all_files = map(os.path.expanduser, all_files)
+  all_files = list(map(os.path.expanduser, all_files))
 
   for file_name in all_files:
     if not os.path.isfile(file_name):
@@ -181,7 +181,7 @@ def CopyRequiredFiles(dest_files_root, allow_list):
       logging.exception("Copying '%s' to %s failed", file_name, lib_dir)
       sys.exit(1)
 
-  for source_dir, target_dir in RECURSE_DIRS.iteritems():
+  for source_dir, target_dir in RECURSE_DIRS.items():
     logging.debug('Processing directory %s', source_dir)
     full_path = os.path.expanduser(source_dir)
     if not os.path.isdir(full_path):
@@ -212,7 +212,7 @@ def WrapExecutableFiles(dest_files_root, ld_linux):
     local_exec_wrapped = local_exec + ".bin"
     shutil.move(local_exec, local_exec_wrapped)
 
-    fd = os.open(local_exec, os.O_WRONLY | os.O_CREAT, 0733)
+    fd = os.open(local_exec, os.O_WRONLY | os.O_CREAT, 0o733)
     with os.fdopen(fd, 'w') as script:
       script.write('#!/bin/sh\n')
       script.write('# Auto-generated wrapper script\n')
@@ -249,7 +249,7 @@ def GenerateZipFile(base_name, root_dir):
   try:
     subprocess.Popen(['zip', '-r', '-9', base_name, '.'],
                      stdout=subprocess.PIPE).communicate()[0]
-  except OSError, e:
+  except OSError as e:
    logging.error('Execution failed:%s', e.strerror)
    return False
   finally:
diff --git a/build_library/generate_grub_hashes.py b/build_library/generate_grub_hashes.py
index 419e62e401..51660c26c7 100755
--- a/build_library/generate_grub_hashes.py
+++ b/build_library/generate_grub_hashes.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import hashlib
 import json
@@ -7,7 +7,7 @@ import string
 import subprocess
 import sys
 
-filename = sys.argv[1] 
+filename = sys.argv[1]
 grubdir = sys.argv[2]
 outputdir = sys.argv[3]
 version = sys.argv[4]
diff --git a/build_library/generate_kernel_hash.sh b/build_library/generate_kernel_hash.sh
index 429fe9cb7d..6e7549fe93 100755
--- a/build_library/generate_kernel_hash.sh
+++ b/build_library/generate_kernel_hash.sh
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 import hashlib
 import json
@@ -10,4 +10,4 @@ version=sys.argv[2]
 
 with open(path, "rb") as f:
     kernel = f.read()
-    print json.dumps({"9": {"binaryvalues": [{"prefix": "grub_linux", "values": [{"value": hashlib.sha1(kernel).hexdigest(), "description": "flatcar-%s" % version}]}]}})
+    print(json.dumps({"9": {"binaryvalues": [{"prefix": "grub_linux", "values": [{"value": hashlib.sha1(kernel).hexdigest(), "description": "flatcar-%s" % version}]}]}}))