diff --git a/subcmds/sync.py b/subcmds/sync.py
index 0c0f0cf..e4e7a97 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -1190,6 +1190,45 @@
             'release.  Use `--auto-gc` instead.', file=sys.stderr)
       opt.auto_gc = True
 
+  def _ValidateOptionsWithManifest(self, opt, mp):
+    """Like ValidateOptions, but after we've updated the manifest.
+
+    Needed to handle sync-xxx option defaults in the manifest.
+
+    Args:
+      opt: The options to process.
+      mp: The manifest project to pull defaults from.
+    """
+    if not opt.jobs:
+      # If the user hasn't made a choice, use the manifest value.
+      opt.jobs = mp.manifest.default.sync_j
+    if opt.jobs:
+      # If --jobs has a non-default value, propagate it as the default for
+      # --jobs-xxx flags too.
+      if not opt.jobs_network:
+        opt.jobs_network = opt.jobs
+      if not opt.jobs_checkout:
+        opt.jobs_checkout = opt.jobs
+    else:
+      # Neither user nor manifest have made a choice, so setup defaults.
+      if not opt.jobs_network:
+        opt.jobs_network = 1
+      if not opt.jobs_checkout:
+        opt.jobs_checkout = DEFAULT_LOCAL_JOBS
+      opt.jobs = os.cpu_count()
+
+    # Try to stay under user rlimit settings.
+    #
+    # Since each worker requires at 3 file descriptors to run `git fetch`, use
+    # that to scale down the number of jobs.  Unfortunately there isn't an easy
+    # way to determine this reliably as systems change, but it was last measured
+    # by hand in 2011.
+    soft_limit, _ = _rlimit_nofile()
+    jobs_soft_limit = max(1, (soft_limit - 5) // 3)
+    opt.jobs = min(opt.jobs, jobs_soft_limit)
+    opt.jobs_network = min(opt.jobs_network, jobs_soft_limit)
+    opt.jobs_checkout = min(opt.jobs_checkout, jobs_soft_limit)
+
   def Execute(self, opt, args):
     manifest = self.outer_manifest
     if not opt.outer_manifest:
@@ -1240,35 +1279,9 @@
     else:
       print('Skipping update of local manifest project.')
 
-    # Now that the manifests are up-to-date, setup the jobs value.
-    if opt.jobs is None:
-      # User has not made a choice, so use the manifest settings.
-      opt.jobs = mp.default.sync_j
-    if opt.jobs is not None:
-      # Neither user nor manifest have made a choice.
-      if opt.jobs_network is None:
-        opt.jobs_network = opt.jobs
-      if opt.jobs_checkout is None:
-        opt.jobs_checkout = opt.jobs
-    # Setup defaults if jobs==0.
-    if not opt.jobs:
-      if not opt.jobs_network:
-        opt.jobs_network = 1
-      if not opt.jobs_checkout:
-        opt.jobs_checkout = DEFAULT_LOCAL_JOBS
-      opt.jobs = os.cpu_count()
-
-    # Try to stay under user rlimit settings.
-    #
-    # Since each worker requires at 3 file descriptors to run `git fetch`, use
-    # that to scale down the number of jobs.  Unfortunately there isn't an easy
-    # way to determine this reliably as systems change, but it was last measured
-    # by hand in 2011.
-    soft_limit, _ = _rlimit_nofile()
-    jobs_soft_limit = max(1, (soft_limit - 5) // 3)
-    opt.jobs = min(opt.jobs, jobs_soft_limit)
-    opt.jobs_network = min(opt.jobs_network, jobs_soft_limit)
-    opt.jobs_checkout = min(opt.jobs_checkout, jobs_soft_limit)
+    # Now that the manifests are up-to-date, setup options whose defaults might
+    # be in the manifest.
+    self._ValidateOptionsWithManifest(opt, mp)
 
     superproject_logging_data = {}
     self._UpdateProjectsRevisionId(opt, args, superproject_logging_data,
diff --git a/tests/test_subcmds_sync.py b/tests/test_subcmds_sync.py
index 13f3f87..236d54e 100644
--- a/tests/test_subcmds_sync.py
+++ b/tests/test_subcmds_sync.py
@@ -13,11 +13,13 @@
 # limitations under the License.
 """Unittests for the subcmds/sync.py module."""
 
+import os
 import unittest
 from unittest import mock
 
 import pytest
 
+import command
 from subcmds import sync
 
 
@@ -43,6 +45,51 @@
     assert cmd._GetCurrentBranchOnly(opts, cmd.manifest) == result
 
 
+# Used to patch os.cpu_count() for reliable results.
+OS_CPU_COUNT = 24
+
+@pytest.mark.parametrize('argv, jobs_manifest, jobs, jobs_net, jobs_check', [
+  # No user or manifest settings.
+  ([], None, OS_CPU_COUNT, 1, command.DEFAULT_LOCAL_JOBS),
+  # No user settings, so manifest settings control.
+  ([], 3, 3, 3, 3),
+  # User settings, but no manifest.
+  (['--jobs=4'], None, 4, 4, 4),
+  (['--jobs=4', '--jobs-network=5'], None, 4, 5, 4),
+  (['--jobs=4', '--jobs-checkout=6'], None, 4, 4, 6),
+  (['--jobs=4', '--jobs-network=5', '--jobs-checkout=6'], None, 4, 5, 6),
+  (['--jobs-network=5'], None, OS_CPU_COUNT, 5, command.DEFAULT_LOCAL_JOBS),
+  (['--jobs-checkout=6'], None, OS_CPU_COUNT, 1, 6),
+  (['--jobs-network=5', '--jobs-checkout=6'], None, OS_CPU_COUNT, 5, 6),
+  # User settings with manifest settings.
+  (['--jobs=4'], 3, 4, 4, 4),
+  (['--jobs=4', '--jobs-network=5'], 3, 4, 5, 4),
+  (['--jobs=4', '--jobs-checkout=6'], 3, 4, 4, 6),
+  (['--jobs=4', '--jobs-network=5', '--jobs-checkout=6'], 3, 4, 5, 6),
+  (['--jobs-network=5'], 3, 3, 5, 3),
+  (['--jobs-checkout=6'], 3, 3, 3, 6),
+  (['--jobs-network=5', '--jobs-checkout=6'], 3, 3, 5, 6),
+  # Settings that exceed rlimits get capped.
+  (['--jobs=1000000'], None, 83, 83, 83),
+  ([], 1000000, 83, 83, 83),
+])
+def test_cli_jobs(argv, jobs_manifest, jobs, jobs_net, jobs_check):
+  """Tests --jobs option behavior."""
+  mp = mock.MagicMock()
+  mp.manifest.default.sync_j = jobs_manifest
+
+  cmd = sync.Sync()
+  opts, args = cmd.OptionParser.parse_args(argv)
+  cmd.ValidateOptions(opts, args)
+
+  with mock.patch.object(sync, '_rlimit_nofile', return_value=(256, 256)):
+    with mock.patch.object(os, 'cpu_count', return_value=OS_CPU_COUNT):
+      cmd._ValidateOptionsWithManifest(opts, mp)
+      assert opts.jobs == jobs
+      assert opts.jobs_network == jobs_net
+      assert opts.jobs_checkout == jobs_check
+
+
 class GetPreciousObjectsState(unittest.TestCase):
   """Tests for _GetPreciousObjectsState."""