diff --git a/error.py b/error.py
index 225eb59..8bb64b8 100644
--- a/error.py
+++ b/error.py
@@ -13,6 +13,10 @@
 # limitations under the License.
 
 
+# URL to file bug reports for repo tool issues.
+BUG_REPORT_URL = 'https://bugs.chromium.org/p/gerrit/issues/entry?template=Repo+tool+issue'
+
+
 class ManifestParseError(Exception):
   """Failed to parse the manifest file.
   """
diff --git a/git_superproject.py b/git_superproject.py
new file mode 100644
index 0000000..3e87e92
--- /dev/null
+++ b/git_superproject.py
@@ -0,0 +1,149 @@
+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Provide functionality to get all projects and their SHAs from Superproject.
+
+For more information on superproject, check out:
+https://en.wikibooks.org/wiki/Git/Submodules_and_Superprojects
+
+Examples:
+  superproject = Superproject()
+  project_shas = superproject.GetAllProjectsSHAs()
+"""
+
+import os
+import sys
+
+from error import GitError
+from git_command import GitCommand
+import platform_utils
+
+
+class Superproject(object):
+  """Get SHAs from superproject.
+
+  It does a 'git clone' of superproject and 'git ls-tree' to get list of SHAs for all projects.
+  It contains project_shas which is a dictionary with project/sha entries.
+  """
+  def __init__(self, repodir, superproject_dir='exp-superproject'):
+    """Initializes superproject.
+
+    Args:
+      repodir: Path to the .repo/ dir for holding all internal checkout state.
+      superproject_dir: Relative path under |repodir| to checkout superproject.
+    """
+    self._project_shas = None
+    self._repodir = os.path.abspath(repodir)
+    self._superproject_dir = superproject_dir
+    self._superproject_path = os.path.join(self._repodir, superproject_dir)
+
+  @property
+  def project_shas(self):
+    """Returns a dictionary of projects and their SHAs."""
+    return self._project_shas
+
+  def _Clone(self, url, branch=None):
+    """Do a 'git clone' for the given url and branch.
+
+    Args:
+      url: superproject's url to be passed to git clone.
+      branch: the branchname to be passed as argument to git clone.
+
+    Returns:
+      True if 'git clone <url> <branch>' is successful, or False.
+    """
+    cmd = ['clone', url, '--depth', '1']
+    if branch:
+      cmd += ['--branch', branch]
+    p = GitCommand(None,
+                   cmd,
+                   cwd=self._superproject_path,
+                   capture_stdout=True,
+                   capture_stderr=True)
+    retval = p.Wait()
+    if retval:
+      # `git clone` is documented to produce an exit status of `128` if
+      # the requested url or branch are not present in the configuration.
+      print('repo: error: git clone call failed with return code: %r, stderr: %r' %
+            (retval, p.stderr), file=sys.stderr)
+      return False
+    return True
+
+  def _LsTree(self):
+    """Returns the data from 'git ls-tree -r HEAD'.
+
+    Works only in git repositories.
+
+    Returns:
+      data: data returned from 'git ls-tree -r HEAD' instead of None.
+    """
+    git_dir = os.path.join(self._superproject_path, 'superproject')
+    if not os.path.exists(git_dir):
+      raise GitError('git ls-tree. Missing drectory: %s' % git_dir)
+    data = None
+    cmd = ['ls-tree', '-z', '-r', 'HEAD']
+    p = GitCommand(None,
+                   cmd,
+                   cwd=git_dir,
+                   capture_stdout=True,
+                   capture_stderr=True)
+    retval = p.Wait()
+    if retval == 0:
+      data = p.stdout
+    else:
+      # `git clone` is documented to produce an exit status of `128` if
+      # the requested url or branch are not present in the configuration.
+      print('repo: error: git ls-tree call failed with return code: %r, stderr: %r' % (
+          retval, p.stderr), file=sys.stderr)
+    return data
+
+  def GetAllProjectsSHAs(self, url, branch=None):
+    """Get SHAs for all projects from superproject and save them in _project_shas.
+
+    Args:
+      url: superproject's url to be passed to git clone.
+      branch: the branchname to be passed as argument to git clone.
+
+    Returns:
+      A dictionary with the projects/SHAs instead of None.
+    """
+    if not url:
+      raise ValueError('url argument is not supplied.')
+    if os.path.exists(self._superproject_path):
+      platform_utils.rmtree(self._superproject_path)
+    os.mkdir(self._superproject_path)
+
+    # TODO(rtenneti): we shouldn't be cloning the repo from scratch every time.
+    if not self._Clone(url, branch):
+      raise GitError('git clone failed for url: %s' % url)
+
+    data = self._LsTree()
+    if not data:
+      raise GitError('git ls-tree failed for url: %s' % url)
+
+    # Parse lines like the following to select lines starting with '160000' and
+    # build a dictionary with project path (last element) and its SHA (3rd element).
+    #
+    # 160000 commit 2c2724cb36cd5a9cec6c852c681efc3b7c6b86ea\tart\x00
+    # 120000 blob acc2cbdf438f9d2141f0ae424cec1d8fc4b5d97f\tbootstrap.bash\x00
+    shas = {}
+    for line in data.split('\x00'):
+      ls_data = line.split(None, 3)
+      if not ls_data:
+        break
+      if ls_data[0] == '160000':
+        shas[ls_data[3]] = ls_data[2]
+
+    self._project_shas = shas
+    return shas
diff --git a/project.py b/project.py
index 6c6534d..17c75b4 100644
--- a/project.py
+++ b/project.py
@@ -1197,6 +1197,9 @@
       raise ManifestInvalidRevisionError('revision %s in %s not found' %
                                          (self.revisionExpr, self.name))
 
+  def SetRevisionId(self, revisionId):
+    self.revisionId = revisionId
+
   def Sync_LocalHalf(self, syncbuf, force_sync=False, submodules=False):
     """Perform only the local IO portion of the sync process.
        Network access is not required.
diff --git a/subcmds/sync.py b/subcmds/sync.py
index 3482946..d6b8f9d 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -51,11 +51,12 @@
 from git_command import GIT, git_require
 from git_config import GetUrlCookieFile
 from git_refs import R_HEADS, HEAD
+import git_superproject
 import gitc_utils
 from project import Project
 from project import RemoteSpec
 from command import Command, MirrorSafeCommand
-from error import RepoChangedException, GitError, ManifestParseError
+from error import BUG_REPORT_URL, RepoChangedException, GitError, ManifestParseError
 import platform_utils
 from project import SyncBuffer
 from progress import Progress
@@ -241,6 +242,8 @@
     p.add_option('--fetch-submodules',
                  dest='fetch_submodules', action='store_true',
                  help='fetch submodules from server')
+    p.add_option('--use-superproject', action='store_true',
+                 help='use the manifest superproject to sync projects')
     p.add_option('--no-tags',
                  dest='tags', default=True, action='store_false',
                  help="don't fetch tags")
@@ -894,6 +897,41 @@
                                     missing_ok=True,
                                     submodules_ok=opt.fetch_submodules)
 
+    if opt.use_superproject:
+      if not self.manifest.superproject:
+        print('error: superproject tag is not defined in manifest.xml',
+              file=sys.stderr)
+        sys.exit(1)
+      print('WARNING: --use-superproject is experimental and not '
+            'for general use', file=sys.stderr)
+      superproject_url = self.manifest.superproject['remote'].url
+      if not superproject_url:
+        print('error: superproject URL is not defined in manifest.xml',
+              file=sys.stderr)
+        sys.exit(1)
+      superproject = git_superproject.Superproject(self.manifest.repodir)
+      try:
+        superproject_shas = superproject.GetAllProjectsSHAs(url=superproject_url)
+      except Exception as e:
+        print('error: Cannot get project SHAs for %s: %s: %s' %
+              (superproject_url, type(e).__name__, str(e)),
+              file=sys.stderr)
+        sys.exit(1)
+      projects_missing_shas = []
+      for project in all_projects:
+        path = project.relpath
+        if not path:
+          continue
+        sha = superproject_shas.get(path)
+        if sha:
+          project.SetRevisionId(sha)
+        else:
+          projects_missing_shas.append(path)
+      if projects_missing_shas:
+        print('error: please file a bug using %s to report missing shas for: %s' %
+              (BUG_REPORT_URL, projects_missing_shas), file=sys.stderr)
+        sys.exit(1)
+
     err_network_sync = False
     err_update_projects = False
     err_checkout = False
diff --git a/tests/test_git_superproject.py b/tests/test_git_superproject.py
new file mode 100644
index 0000000..67a75a1
--- /dev/null
+++ b/tests/test_git_superproject.py
@@ -0,0 +1,82 @@
+# Copyright (C) 2021 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unittests for the git_superproject.py module."""
+
+import os
+import tempfile
+import unittest
+from unittest import mock
+
+from error import GitError
+import git_superproject
+import platform_utils
+
+
+class SuperprojectTestCase(unittest.TestCase):
+  """TestCase for the Superproject module."""
+
+  def setUp(self):
+    """Set up superproject every time."""
+    self.tempdir = tempfile.mkdtemp(prefix='repo_tests')
+    self.repodir = os.path.join(self.tempdir, '.repo')
+    os.mkdir(self.repodir)
+    self._superproject = git_superproject.Superproject(self.repodir)
+
+  def tearDown(self):
+    """Tear down superproject every time."""
+    platform_utils.rmtree(self.tempdir)
+
+  def test_superproject_get_project_shas_no_url(self):
+    """Test with no url."""
+    with self.assertRaises(ValueError):
+      self._superproject.GetAllProjectsSHAs(url=None)
+
+  def test_superproject_get_project_shas_invalid_url(self):
+    """Test with an invalid url."""
+    with self.assertRaises(GitError):
+      self._superproject.GetAllProjectsSHAs(url='localhost')
+
+  def test_superproject_get_project_shas_invalid_branch(self):
+    """Test with an invalid branch."""
+    with self.assertRaises(GitError):
+      self._superproject.GetAllProjectsSHAs(
+          url='sso://android/platform/superproject',
+          branch='junk')
+
+  def test_superproject_get_project_shas_mock_clone(self):
+    """Test with _Clone failing."""
+    with self.assertRaises(GitError):
+      with mock.patch.object(self._superproject, '_Clone', return_value=False):
+        self._superproject.GetAllProjectsSHAs(url='localhost')
+
+  def test_superproject_get_project_shas_mock_ls_tree(self):
+    """Test with LsTree being a mock."""
+    data = ('120000 blob 158258bdf146f159218e2b90f8b699c4d85b5804\tAndroid.bp\x00'
+            '160000 commit 2c2724cb36cd5a9cec6c852c681efc3b7c6b86ea\tart\x00'
+            '160000 commit e9d25da64d8d365dbba7c8ee00fe8c4473fe9a06\tbootable/recovery\x00'
+            '120000 blob acc2cbdf438f9d2141f0ae424cec1d8fc4b5d97f\tbootstrap.bash\x00'
+            '160000 commit ade9b7a0d874e25fff4bf2552488825c6f111928\tbuild/bazel\x00')
+    with mock.patch.object(self._superproject, '_Clone', return_value=True):
+      with mock.patch.object(self._superproject, '_LsTree', return_value=data):
+        shas = self._superproject.GetAllProjectsSHAs(url='localhost', branch='junk')
+        self.assertEqual(shas, {
+            'art': '2c2724cb36cd5a9cec6c852c681efc3b7c6b86ea',
+            'bootable/recovery': 'e9d25da64d8d365dbba7c8ee00fe8c4473fe9a06',
+            'build/bazel': 'ade9b7a0d874e25fff4bf2552488825c6f111928'
+        })
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/tests/test_manifest_xml.py b/tests/test_manifest_xml.py
index e2c83af..370eb4f 100644
--- a/tests/test_manifest_xml.py
+++ b/tests/test_manifest_xml.py
@@ -232,6 +232,7 @@
 """)
     self.assertEqual(manifest.superproject['name'], 'superproject')
     self.assertEqual(manifest.superproject['remote'].name, 'test-remote')
+    self.assertEqual(manifest.superproject['remote'].url, 'http://localhost/superproject')
     self.assertEqual(
         manifest.ToXml().toxml(),
         '<?xml version="1.0" ?><manifest>' +
@@ -245,20 +246,21 @@
     manifest = self.getXmlManifest("""
 <manifest>
   <remote name="default-remote" fetch="http://localhost" />
-  <remote name="test-remote" fetch="http://localhost" />
+  <remote name="superproject-remote" fetch="http://localhost" />
   <default remote="default-remote" revision="refs/heads/main" />
-  <superproject name="superproject" remote="test-remote"/>
+  <superproject name="platform/superproject" remote="superproject-remote"/>
 </manifest>
 """)
-    self.assertEqual(manifest.superproject['name'], 'superproject')
-    self.assertEqual(manifest.superproject['remote'].name, 'test-remote')
+    self.assertEqual(manifest.superproject['name'], 'platform/superproject')
+    self.assertEqual(manifest.superproject['remote'].name, 'superproject-remote')
+    self.assertEqual(manifest.superproject['remote'].url, 'http://localhost/platform/superproject')
     self.assertEqual(
         manifest.ToXml().toxml(),
         '<?xml version="1.0" ?><manifest>' +
         '<remote name="default-remote" fetch="http://localhost"/>' +
-        '<remote name="test-remote" fetch="http://localhost"/>' +
+        '<remote name="superproject-remote" fetch="http://localhost"/>' +
         '<default remote="default-remote" revision="refs/heads/main"/>' +
-        '<superproject name="superproject" remote="test-remote"/>' +
+        '<superproject name="platform/superproject" remote="superproject-remote"/>' +
         '</manifest>')
 
   def test_superproject_with_defalut_remote(self):