diff --git a/git_pw/api.py b/git_pw/api.py
index c62a352..0a90072 100644
--- a/git_pw/api.py
+++ b/git_pw/api.py
@@ -232,6 +232,11 @@ def version() -> ty.Tuple[int, int]:
     return (1, 0)
 
 
+def get(url: str, params: ty.Optional[Filters]) -> ty.Dict:
+    """Get a JSON document from the API and return it as a dict."""
+    return _get(url, params, stream=False).json()
+
+
 def download(
     url: str,
     params: ty.Optional[Filters] = None,
diff --git a/git_pw/series.py b/git_pw/series.py
index 1a46bc7..b121c8e 100644
--- a/git_pw/series.py
+++ b/git_pw/series.py
@@ -25,8 +25,15 @@
     ),
 )
 @click.argument('series_id', type=click.INT)
+@click.option(
+    '--deps/--no-deps',
+    'deps',
+    default=False,
+    help='Download any dependencies this series may have, and apply them'
+    'first.',
+)
 @click.argument('args', nargs=-1, type=click.UNPROCESSED)
-def apply_cmd(series_id, args):
+def apply_cmd(series_id, args, deps):
     """Apply series.
 
     Apply a series locally using the 'git-am' command. Any additional ARGS
@@ -35,9 +42,31 @@ def apply_cmd(series_id, args):
     LOG.debug('Applying series: id=%d, args=%s', series_id, ' '.join(args))
 
     series = api.detail('series', series_id)
-    mbox = api.download(series['mbox'])
 
-    utils.git_am(mbox, args)
+    # .mbox files are applied in the order they appear in this list.
+    to_apply = []
+
+    if deps:
+        if dependencies := series.get('dependencies'):
+            to_apply.extend(
+                map(lambda url: api.get(url)['mbox'], dependencies)
+            )
+        else:
+            # Notify the user that dependency information could not be found.
+            LOG.warning(
+                "Dependency information was not found for this series."
+            )
+            LOG.warning(
+                "Either dependencies are unsupported by this Patchwork"
+                "server or the feature is disabled for this project."
+            )
+            LOG.warning("No dependencies will be applied.")
+
+    to_apply.append(series['mbox'])
+
+    for mbox_url in to_apply:
+        mbox = api.download(mbox_url)
+        utils.git_am(mbox, args)
 
 
 @click.command(name='download')
diff --git a/tests/test_series.py b/tests/test_series.py
index 4dd6a5e..5eea227 100644
--- a/tests/test_series.py
+++ b/tests/test_series.py
@@ -6,11 +6,14 @@
 from git_pw import series
 
 
+@mock.patch('git_pw.api.get')
 @mock.patch('git_pw.api.detail')
 @mock.patch('git_pw.api.download')
 @mock.patch('git_pw.utils.git_am')
 class ApplyTestCase(unittest.TestCase):
-    def test_apply_without_args(self, mock_git_am, mock_download, mock_detail):
+    def test_apply_without_args(
+        self, mock_git_am, mock_download, mock_detail, mock_api_get
+    ):
         """Validate calling with no arguments."""
 
         rsp = {'mbox': 'http://example.com/api/patches/123/mbox/'}
@@ -25,7 +28,9 @@ def test_apply_without_args(self, mock_git_am, mock_download, mock_detail):
         mock_download.assert_called_once_with(rsp['mbox'])
         mock_git_am.assert_called_once_with(mock_download.return_value, ())
 
-    def test_apply_with_args(self, mock_git_am, mock_download, mock_detail):
+    def test_apply_with_args(
+        self, mock_git_am, mock_download, mock_detail, mock_api_get
+    ):
         """Validate passthrough of arbitrary arguments to git-am."""
 
         rsp = {'mbox': 'http://example.com/api/patches/123/mbox/'}
@@ -42,6 +47,63 @@ def test_apply_with_args(self, mock_git_am, mock_download, mock_detail):
             mock_download.return_value, ('-3',)
         )
 
+    def test_apply_with_deps_unsupported(
+        self, mock_git_am, mock_download, mock_detail, mock_api_get
+    ):
+        """
+        Validate that a series is applied when dependencies are
+        requested and dependencies do not appear in the API.
+        """
+
+        rsp = {'mbox': 'http://example.com/api/series/123/mbox/'}
+        mock_detail.return_value = rsp
+        mock_download.return_value = 'test.patch'
+
+        runner = CLIRunner()
+        result = runner.invoke(series.apply_cmd, ['123', '--deps'])
+
+        assert result.exit_code == 0, result
+        mock_detail.assert_called_once_with('series', 123)
+        mock_download.assert_called_once_with(rsp['mbox'])
+        mock_git_am.assert_called_once_with(mock_download.return_value, ())
+
+    def test_apply_with_deps(
+        self, mock_git_am, mock_download, mock_detail, mock_api_get
+    ):
+        """Validate that dependencies are applied when flag is given."""
+        dep_ids = [
+            '120',
+            '121',
+            '122',
+        ]
+        dependencies = list(
+            map(lambda x: f"http://example.com/api/series/{x}/", dep_ids)
+        )
+        dep_details = list(map(lambda x: {"mbox": f"{x}mbox/"}, dependencies))
+        mboxes = list(map(lambda x: x["mbox"], dep_details))
+        mboxes.append('http://example.com/api/series/123/mbox/')
+        files = list(map(lambda x: f"series_{x}.mbox", [*dep_ids, '123']))
+
+        rsp_base = {
+            'mbox': 'http://example.com/api/series/123/mbox/',
+            'dependencies': dependencies,
+        }
+
+        mock_detail.return_value = rsp_base
+        mock_api_get.side_effect = dep_details
+        mock_download.side_effect = files
+
+        runner = CLIRunner()
+        result = runner.invoke(series.apply_cmd, ['123', '--deps'])
+
+        assert result.exit_code == 0, result
+        mock_detail.assert_called_once_with('series', 123)
+        mock_api_get.assert_has_calls(
+            map(lambda x: mock.call(x), dependencies)
+        )
+        mock_download.assert_has_calls(map(lambda x: mock.call(x), mboxes))
+        mock_git_am.assert_has_calls(map(lambda x: mock.call(x, ()), files))
+
 
 @mock.patch('git_pw.api.detail')
 @mock.patch('git_pw.api.download')
@@ -125,6 +187,8 @@ def _get_series(**kwargs):
             'received_all': True,
             'cover_letter': None,
             'patches': [],
+            'dependencies': [],
+            'dependents': [],
         }
 
         rsp.update(**kwargs)