diff --git a/command.py b/command.py
index 8e93787..724e4c5 100644
--- a/command.py
+++ b/command.py
@@ -15,9 +15,11 @@
 
 import os
 import optparse
+import re
 import sys
 
 from error import NoSuchProjectError
+from error import InvalidProjectGroupsError
 
 class Command(object):
   """Base class for any command line action in repo.
@@ -63,9 +65,16 @@
     all = self.manifest.projects
     result = []
 
+    mp = self.manifest.manifestProject
+
+    groups = mp.config.GetString('manifest.groups')
+    if groups:
+      groups = re.split('[,\s]+', groups)
+
     if not args:
       for project in all.values():
-        if missing_ok or project.Exists:
+        if ((missing_ok or project.Exists) and
+            project.MatchesGroups(groups)):
           result.append(project)
     else:
       by_path = None
@@ -102,6 +111,8 @@
           raise NoSuchProjectError(arg)
         if not missing_ok and not project.Exists:
           raise NoSuchProjectError(arg)
+        if not project.MatchesGroups(groups):
+          raise InvalidProjectGroupsError(arg)
 
         result.append(project)
 
diff --git a/docs/manifest-format.txt b/docs/manifest-format.txt
index 21f19db..a7bb156 100644
--- a/docs/manifest-format.txt
+++ b/docs/manifest-format.txt
@@ -48,6 +48,7 @@
     <!ATTLIST project path     CDATA #IMPLIED>
     <!ATTLIST project remote   IDREF #IMPLIED>
     <!ATTLIST project revision CDATA #IMPLIED>
+    <!ATTLIST project groups   CDATA #IMPLIED>
   
     <!ELEMENT remove-project (EMPTY)>
     <!ATTLIST remove-project name  CDATA #REQUIRED>
@@ -158,6 +159,10 @@
 been extensively tested.  If not supplied the revision given by
 the default element is used.
 
+Attribute `groups`: List of groups to which this project belongs,
+whitespace or comma separated.  All projects are part of the group
+"default" unless "-default" is specified in the list of groups.
+
 Element remove-project
 ----------------------
 
diff --git a/error.py b/error.py
index 812585c..78c5c0e 100644
--- a/error.py
+++ b/error.py
@@ -77,6 +77,18 @@
       return 'in current directory'
     return self.name
 
+
+class InvalidProjectGroupsError(Exception):
+  """A specified project is not suitable for the specified groups
+  """
+  def __init__(self, name=None):
+    self.name = name
+
+  def __str__(self):
+    if self.Name is None:
+      return 'in current directory'
+    return self.name
+
 class RepoChangedException(Exception):
   """Thrown if 'repo sync' results in repo updating its internal
      repo or manifest repositories.  In this special case we must
diff --git a/manifest_xml.py b/manifest_xml.py
index 4453869..a250382 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -119,6 +119,12 @@
   def Save(self, fd, peg_rev=False):
     """Write the current manifest out to the given file descriptor.
     """
+    mp = self.manifestProject
+
+    groups = mp.config.GetString('manifest.groups')
+    if groups:
+      groups = re.split('[,\s]+', groups)
+
     doc = xml.dom.minidom.Document()
     root = doc.createElement('manifest')
     doc.appendChild(root)
@@ -167,6 +173,10 @@
 
     for p in sort_projects:
       p = self.projects[p]
+
+      if not p.MatchesGroups(groups):
+        continue
+
       e = doc.createElement('project')
       root.appendChild(e)
       e.setAttribute('name', p.name)
@@ -190,6 +200,9 @@
         ce.setAttribute('dest', c.dest)
         e.appendChild(ce)
 
+      if p.groups:
+        e.setAttribute('groups', ','.join(p.groups))
+
     if self._repo_hooks_project:
       root.appendChild(doc.createTextNode(''))
       e = doc.createElement('repo-hooks')
@@ -504,6 +517,12 @@
     else:
       rebase = rebase.lower() in ("yes", "true", "1")
 
+    groups = node.getAttribute('groups')
+    if groups:
+      groups = re.split('[,\s]+', groups)
+    else:
+      groups = None
+
     if self.IsMirror:
       relpath = None
       worktree = None
@@ -520,7 +539,8 @@
                       relpath = path,
                       revisionExpr = revisionExpr,
                       revisionId = None,
-                      rebase = rebase)
+                      rebase = rebase,
+                      groups = groups)
 
     for n in node.childNodes:
       if n.nodeName == 'copyfile':
diff --git a/project.py b/project.py
index 303abe3..b2eaa87 100644
--- a/project.py
+++ b/project.py
@@ -504,7 +504,8 @@
                relpath,
                revisionExpr,
                revisionId,
-               rebase = True):
+               rebase = True,
+               groups = None):
     self.manifest = manifest
     self.name = name
     self.remote = remote
@@ -524,6 +525,7 @@
       self.revisionId = revisionId
 
     self.rebase = rebase
+    self.groups = groups
 
     self.snapshots = {}
     self.copyfiles = []
@@ -645,6 +647,45 @@
 
     return heads
 
+  def MatchesGroups(self, manifest_groups):
+    """Returns true if the manifest groups specified at init should cause
+       this project to be synced.
+       Prefixing a manifest group with "-" inverts the meaning of a group.
+       All projects are implicitly labelled with "default" unless they are
+       explicitly labelled "-default".
+       If any non-inverted manifest groups are specified, the default label
+       is ignored.
+       Specifying only inverted groups implies "default".
+    """
+    project_groups = self.groups
+    if not manifest_groups:
+      return not project_groups or not "-default" in project_groups
+
+    if not project_groups:
+      project_groups = ["default"]
+    elif not ("default" in project_groups or "-default" in project_groups):
+      project_groups.append("default")
+
+    plus_groups = [x for x in manifest_groups if not x.startswith("-")]
+    minus_groups = [x[1:] for x in manifest_groups if x.startswith("-")]
+
+    if not plus_groups:
+      plus_groups.append("default")
+
+    for group in minus_groups:
+      if group in project_groups:
+        # project was excluded by -group
+        return False
+
+    for group in plus_groups:
+      if group in project_groups:
+        # project was included by group
+        return True
+
+    # groups were specified that did not include this project
+    if plus_groups:
+      return False
+    return True
 
 ## Status Display ##
 
@@ -2091,7 +2132,8 @@
                      remote = RemoteSpec('origin'),
                      relpath = '.repo/%s' % name,
                      revisionExpr = 'refs/heads/master',
-                     revisionId = None)
+                     revisionId = None,
+                     groups = None)
 
   def PreSync(self):
     if self.Exists:
diff --git a/repo b/repo
index 1977d63..75fe9ec 100755
--- a/repo
+++ b/repo
@@ -28,7 +28,7 @@
 del magic
 
 # increment this whenever we make important changes to this script
-VERSION = (1, 14)
+VERSION = (1, 15)
 
 # increment this if the MAINTAINER_KEYS block is modified
 KEYRING_VERSION = (1,0)
@@ -125,6 +125,10 @@
 group.add_option('--depth', type='int', default=None,
                  dest='depth',
                  help='create a shallow clone with given depth; see git clone')
+group.add_option('-g', '--groups',
+                 dest='groups', default="",
+                 help='restrict manifest projects to ones with a specified group',
+                 metavar='GROUP')
 
 
 # Tool
diff --git a/subcmds/init.py b/subcmds/init.py
index 1cba366..6cf39d1 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -86,6 +86,10 @@
     g.add_option('--depth', type='int', default=None,
                  dest='depth',
                  help='create a shallow clone with given depth; see git clone')
+    g.add_option('-g', '--groups',
+                 dest='groups', default="",
+                 help='restrict manifest projects to ones with a specified group',
+                 metavar='GROUP')
 
     # Tool
     g = p.add_option_group('repo Version options')
@@ -135,6 +139,8 @@
       r.ResetFetch()
       r.Save()
 
+    m.config.SetString('manifest.groups', opt.groups)
+
     if opt.reference:
       m.config.SetString('repo.reference', opt.reference)
 
diff --git a/subcmds/sync.py b/subcmds/sync.py
index 74b3f18..63227af 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -277,7 +277,7 @@
 
   def UpdateProjectList(self):
     new_project_paths = []
-    for project in self.manifest.projects.values():
+    for project in self.GetProjects(None, missing_ok=True):
       if project.relpath:
         new_project_paths.append(project.relpath)
     file_name = 'project.list'
@@ -306,7 +306,8 @@
                              worktree = os.path.join(self.manifest.topdir, path),
                              relpath = path,
                              revisionExpr = 'HEAD',
-                             revisionId = None)
+                             revisionId = None,
+                             groups = None)
 
               if project.IsDirty():
                 print >>sys.stderr, 'error: Cannot remove project "%s": \