diff --git a/build/build.py b/build/build.py
index 63db4de864..cbeb1e6e3e 100755
--- a/build/build.py
+++ b/build/build.py
@@ -39,9 +39,9 @@
   build.py --name custom +@manifests +@networking +../my_plugin.js
 """
 
+import logging
 import os
 import re
-import subprocess
 import sys
 
 import shakaBuildHelpers
@@ -127,14 +127,14 @@ def _get_build_file_path(self, name, root):
     build_path = os.path.join(source_base, 'build', 'types', name)
     if (os.path.isfile(local_path) and os.path.isfile(build_path)
         and local_path != build_path):
-      print >> sys.stderr, 'Build file "%s" is ambiguous' % name
+      logging.error('Build file "%s" is ambiguous', name)
       return None
     elif os.path.isfile(local_path):
       return local_path
     elif os.path.isfile(build_path):
       return build_path
     else:
-      print >> sys.stderr, 'Build file not found: ' + name
+      logging.error('Build file not found: %s', name)
       return None
 
   def _combine(self, other):
@@ -162,7 +162,7 @@ def add_core(self):
     core_build.parse_build(['+@core'], os.getcwd())
     core_files = core_build.include
     if self.exclude & core_files:
-      print >> sys.stderr, 'Cannot exclude files from core'
+      logging.error('Cannot exclude files from core')
     self.include |= core_files
 
   def parse_build(self, lines, root):
@@ -196,7 +196,7 @@ def parse_build(self, lines, root):
         is_neg = True
         line = line[1:].strip()
       else:
-        print >> sys.stderr, 'Operation (+/-) required'
+        logging.error('Operation (+/-) required')
         return False
 
       if line[0] == '@':
@@ -221,7 +221,7 @@ def parse_build(self, lines, root):
         if not os.path.isabs(line):
           line = os.path.abspath(os.path.join(root, line))
         if not os.path.isfile(line):
-          print >> sys.stderr, 'Unable to find file ' + line
+          logging.error('Unable to find file: %s', line)
           return False
 
         if is_neg:
@@ -256,7 +256,7 @@ def build_raw(self, extra_opts, is_debug):
 
     cmd_line = ['java', '-jar', jar] + closure_opts + extra_opts + files
     if shakaBuildHelpers.execute_get_code(cmd_line) != 0:
-      print >> sys.stderr, 'Build failed'
+      logging.error('Build failed')
       return False
 
     return True
@@ -281,7 +281,7 @@ def generate_externs(self, name):
 
     cmd_line = ['node', extern_generator, '--output', output] + files
     if shakaBuildHelpers.execute_get_code(cmd_line) != 0:
-      print >> sys.stderr, 'Externs generation failed'
+      logging.error('Externs generation failed')
       return False
 
     return True
@@ -321,7 +321,8 @@ def build_library(self, name, rebuild, is_debug):
         edited_files = [f for f in complete_build.include
                         if os.path.getmtime(f) > build_time]
         if not edited_files:
-          print 'No changes detected, not building.  Use --force to override.'
+          logging.warning('No changes detected, not building.  Use --force '
+                          'to override.')
           return True
 
     opts = ['--create_source_map', result_map, '--js_output_file', result_file,
@@ -363,7 +364,7 @@ def main(args):
     if args[i] == '--name':
       i += 1
       if i == len(args):
-        print >> sys.stderr, '--name requires an argument'
+        logging.error('--name requires an argument')
         return 1
       name = args[i]
     elif args[i] == '--debug':
@@ -374,7 +375,7 @@ def main(args):
       usage()
       return 0
     elif args[i].startswith('--'):
-      print >> sys.stderr, 'Unknown option', args[i]
+      logging.error('Unknown option: %s', args[i])
       usage()
       return 1
     else:
@@ -384,7 +385,7 @@ def main(args):
   if not lines:
     lines = ['+@complete']
 
-  print 'Compiling the library...'
+  logging.info('Compiling the library...')
   custom_build = Build()
   if not custom_build.parse_build(lines, os.getcwd()):
     return 1
diff --git a/build/check.py b/build/check.py
index a5f9e08dd6..830bb13854 100755
--- a/build/check.py
+++ b/build/check.py
@@ -22,6 +22,7 @@
  * Run the linter to check for style violations.
 """
 
+import logging
 import os
 import re
 import sys
@@ -41,7 +42,7 @@ def get(arg):
 
 def check_lint():
   """Runs the linter over the library files."""
-  print 'Running Closure linter...'
+  logging.info('Running Closure linter...')
 
   jsdoc3_tags = ','.join([
       'static', 'summary', 'namespace', 'event', 'description', 'property',
@@ -68,7 +69,7 @@ def check_html_lint():
   if not shakaBuildHelpers.update_node_modules():
     return False
 
-  print 'Running htmlhint...'
+  logging.info('Running htmlhint...')
   htmlhint_path = shakaBuildHelpers.get_node_binary_path('htmlhint')
   base = shakaBuildHelpers.get_source_base()
   files = ['index.html', 'demo/index.html', 'support.html']
@@ -87,14 +88,14 @@ def check_complete():
   Returns:
     True on success, False on failure.
   """
-  print 'Checking that the build files are complete...'
+  logging.info('Checking that the build files are complete...')
 
   complete = build.Build()
   # Normally we don't need to include @core, but because we look at the build
   # object directly, we need to include it here.  When using main(), it will
   # call addCore which will ensure core is included.
   if not complete.parse_build(['+@complete', '+@core'], os.getcwd()):
-    print >> sys.stderr, 'Error parsing complete build'
+    logging.error('Error parsing complete build')
     return False
 
   match = re.compile(r'.*\.js$')
@@ -103,10 +104,10 @@ def check_complete():
   missing_files = set(all_files) - complete.include
 
   if missing_files:
-    print >> sys.stderr, 'There are files missing from the complete build:'
+    logging.error('There are files missing from the complete build:')
     for missing in missing_files:
       # Convert to a path relative to source base.
-      print >> sys.stderr, '  ' + os.path.relpath(missing, base)
+      logging.error('  ' + os.path.relpath(missing, base))
     return False
   return True
 
@@ -117,7 +118,7 @@ def check_tests():
   Returns:
     True on success, False on failure.
   """
-  print 'Checking the tests for type errors...'
+  logging.info('Checking the tests for type errors...')
 
   match = re.compile(r'.*\.js$')
   base = shakaBuildHelpers.get_source_base()
@@ -146,7 +147,7 @@ def main(args):
       usage()
       return 0
     else:
-      print >> sys.stderr, 'Unknown option', arg
+      logging.error('Unknown option: %s', arg)
       usage()
       return 1
 
diff --git a/build/checkversion.py b/build/checkversion.py
index 0984a4a318..998859c84f 100755
--- a/build/checkversion.py
+++ b/build/checkversion.py
@@ -16,9 +16,9 @@
 
 """Checks that all the versions match."""
 
+import logging
 import os
 import re
-import sys
 
 import shakaBuildHelpers
 
@@ -53,26 +53,26 @@ def check_version(_):
 
   ret = 0
   if 'dirty' in git:
-    print >> sys.stderr, 'Git version is dirty.'
+    logging.error('Git version is dirty.')
     ret = 1
   elif 'unknown' in git:
-    print >> sys.stderr, 'Git version is not a tag.'
+    logging.error('Git version is not a tag.')
     ret = 1
   elif not re.match(r'^v[0-9]+\.[0-9]+\.[0-9]+(?:-[a-z0-9]+)?$', git):
-    print >> sys.stderr, 'Git version is a malformed release version.'
-    print >> sys.stderr, 'It should be a \'v\', followed by three numbers'
-    print >> sys.stderr, 'separated by dots, optionally followed by a hyphen'
-    print >> sys.stderr, 'and a pre-release identifier.  See http://semver.org/'
+    logging.error('Git version is a malformed release version.')
+    logging.error('It should be a \'v\', followed by three numbers')
+    logging.error('separated by dots, optionally followed by a hyphen')
+    logging.error('and a pre-release identifier.  See http://semver.org/')
     ret = 1
 
   if 'v' + npm != git:
-    print >> sys.stderr, 'NPM version does not match git version.'
+    logging.error('NPM version does not match git version.')
     ret = 1
   if player != git + '-debug':
-    print >> sys.stderr, 'Player version does not match git version.'
+    logging.error('Player version does not match git version.')
     ret = 1
   if 'v' + changelog != git:
-    print >> sys.stderr, 'Changelog version does not match git version.'
+    logging.error('Changelog version does not match git version.')
     ret = 1
 
   return ret
diff --git a/build/docs.py b/build/docs.py
index 44d47390e5..7bbffd4aca 100755
--- a/build/docs.py
+++ b/build/docs.py
@@ -19,15 +19,17 @@
 This deletes the old documentation first.
 """
 
+import logging
 import os
 import shutil
+import sys
 
 import shakaBuildHelpers
 
 
 def build_docs(_):
   """Builds the source code documentation."""
-  print 'Building the docs...'
+  logging.info('Building the docs...')
 
   base = shakaBuildHelpers.get_source_base()
   shutil.rmtree(os.path.join(base, 'docs', 'api'), ignore_errors=True)
diff --git a/build/gendeps.py b/build/gendeps.py
index 2f8e5861e9..8d7b909a25 100755
--- a/build/gendeps.py
+++ b/build/gendeps.py
@@ -16,6 +16,7 @@
 
 """Creates the Closure dependencies file required to run in uncompiled mode."""
 
+import logging
 import os
 import subprocess
 import sys
@@ -31,7 +32,7 @@
 
 def gen_deps(_):
   """Generates the uncompiled dependencies files."""
-  print 'Generating Closure dependencies...'
+  logging.info('Generating Closure dependencies...')
 
   # Make the dist/ folder, ignore errors.
   base = shakaBuildHelpers.get_source_base()
diff --git a/build/shakaBuildHelpers.py b/build/shakaBuildHelpers.py
index 4693bec328..284619c6a7 100644
--- a/build/shakaBuildHelpers.py
+++ b/build/shakaBuildHelpers.py
@@ -21,6 +21,7 @@
 """
 
 import errno
+import logging
 import os
 import platform
 import re
@@ -114,13 +115,13 @@ def execute_subprocess(args, pipeOut=True):
     The same value as subprocess.Popen.
   """
   if os.environ.get('PRINT_ARGUMENTS'):
-    print ' '.join([quote_argument(x) for x in args])
+    logging.info(' '.join([quote_argument(x) for x in args]))
   try:
     out = subprocess.PIPE if pipeOut else None
     return subprocess.Popen(args, stdin=subprocess.PIPE, stdout=out)
   except OSError as e:
     if e.errno == errno.ENOENT:
-      print >> sys.stderr, '*** A required dependency is missing: ' + args[0]
+      logging.error('*** A required dependency is missing: %s', args[0])
       # Exit early to avoid showing a confusing stack trace.
       sys.exit(1)
     raise
@@ -237,8 +238,8 @@ def update_node_modules():
   version = execute_get_output([cmd, '-v'])
 
   if _parse_version(version) < _parse_version('1.3.12'):
-    print >> sys.stderr, 'npm version is too old, please upgrade.  e.g.:'
-    print >> sys.stderr, '  npm install -g npm'
+    logging.error('npm version is too old, please upgrade.  e.g.:')
+    logging.error('  npm install -g npm')
     return False
 
   # Update the modules.
@@ -256,11 +257,15 @@ def run_main(main):
   Args:
     main: The main function to call.
   """
+  logging.getLogger().setLevel(logging.INFO)
+  fmt = '[%(levelname)s] %(message)s'
+  logging.basicConfig(format=fmt)
+
   try:
     sys.exit(main(sys.argv[1:]))
   except KeyboardInterrupt:
     if os.environ.get('RAISE_INTERRUPT'):
       raise
     print >> sys.stderr  # Clear the current line that has ^C on it.
-    print >> sys.stderr, 'Keyboard interrupt'
+    logging.error('Keyboard interrupt')
     sys.exit(1)
diff --git a/build/stats.py b/build/stats.py
index 125f89f42d..9733fae6e9 100755
--- a/build/stats.py
+++ b/build/stats.py
@@ -33,6 +33,7 @@
 """
 
 import json
+import logging
 import math
 import os
 import string
@@ -822,7 +823,7 @@ def main(args):
       print_help()
       return 0
     else:
-      print >> sys.stderr, 'Unrecognized argument:', arg
+      logging.error('Unrecognized argument: %s', arg)
       print_help()
       return 1
 
@@ -844,18 +845,18 @@ def main(args):
         os.path.join(base, 'dist', 'shaka-player.' + name + '.debug.map')):
       name = os.path.join(base, 'dist', 'shaka-player.' + name + '.debug.map')
     else:
-      print >> sys.stderr, name, 'not found; build Shaka first.'
+      logging.error('"%s" not found; build Shaka first.', name)
       return 1
 
   # Verify arguments are correct.
   if (options.print_sizes + options.print_deps + options.print_tokens +
       options.is_class) != 1:
-    print >> sys.stderr, 'Must include exactly one output type.'
+    logging.error('Must include exactly one output type.')
     print_help()
     return 1
   elif options.in_dot and not options.print_deps and not options.is_class:
-    line = '--dot-format only valid with --function-deps or --class-deps.'
-    print >> sys.stderr, line
+    logging.error('--dot-format only valid with --function-deps or '
+                  '--class-deps.')
     return 1
   else:
     process(open(name).read(), options)
diff --git a/build/test.py b/build/test.py
index b31c702259..d1f1967c84 100755
--- a/build/test.py
+++ b/build/test.py
@@ -16,8 +16,8 @@
 
 """Runs unit and integrations tests on the library."""
 
+import logging
 import platform
-import sys
 
 import build
 import gendeps
@@ -35,20 +35,21 @@ def run_tests_single(args):
   # Get the browsers supported on the local system.
   browsers = _get_browsers()
   if not browsers:
-    print >> sys.stderr, 'Unrecognized system "%s"' % platform.uname()[0]
+    logging.error('Unrecognized system: %s', platform.uname()[0])
     return 1
 
-  print 'Starting tests...'
+  logging.info('Starting tests...')
   if not args:
     # Run tests in all available browsers.
-    print 'Running with platform default:', '--browsers', browsers
+    logging.warning('Running with platform default: --browsers %s', browsers)
     cmd_line = cmd + ['--browsers', browsers]
     return shakaBuildHelpers.execute_get_code(cmd_line)
   else:
     # Run with command-line arguments from the user.
     if '--browsers' not in args:
-      print 'No --browsers specified.'
-      print 'In this mode, browsers must be manually connected to karma.'
+      logging.warning('No --browsers specified.')
+      logging.warning('In this mode, browsers must be manually connected to '
+                      'karma.')
     cmd_line = cmd + args
     return shakaBuildHelpers.execute_get_code(cmd_line)
 
@@ -57,25 +58,26 @@ def run_tests_multiple(args):
   """Runs multiple iterations of the tests when --runs is set."""
   index = args.index('--runs') + 1
   if index == len(args) or args[index].startswith('--'):
-    print >> sys.stderr, 'Argument Error: --runs requires a value.'
+    logging.error('Argument Error: --runs requires a value.')
     return 1
   try:
     runs = int(args[index])
   except ValueError:
-    print >> sys.stderr, 'Argument Error: --runs value must be an integer.'
+    logging.error('Argument Error: --runs value must be an integer.')
     return 1
   if runs <= 0:
-    print >> sys.stderr, 'Argument Error: --runs value must be greater than 0.'
+    logging.error('Argument Error: --runs value must be greater than 0.')
     return 1
 
   results = []
-  print '\nRunning the tests %d times.' % runs
+  logging.info('Running the tests %d times.', runs)
   for _ in range(runs):
     results.append(run_tests_single(args))
 
-  print '\nAll runs completed.'
-  print '%d passed out of %d total runs.' % (results.count(0), len(results))
-  print 'Results (exit code): %r' % results
+  logging.info('\nAll runs completed.')
+  logging.info('%d passed out of %d total runs.', results.count(0),
+               len(results))
+  logging.info('Results (exit code): %r', results)
   return all(result == 0 for result in results)