diff --git a/gcloud/pubsub/__init__.py b/gcloud/pubsub/__init__.py
index 70df328f0987..fb9965ac8b90 100644
--- a/gcloud/pubsub/__init__.py
+++ b/gcloud/pubsub/__init__.py
@@ -12,4 +12,66 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""GCloud Pubsub API wrapper."""
+"""GCloud Pubsub API wrapper.
+
+
+The main concepts with this API are:
+
+- :class:`gcloud.pubsub.topic.Topic` represents an endpoint to which messages
+  can be published using the Cloud Storage Pubsub API.
+
+- :class:`gcloud.pubsub.subscription.Subscription` represents a named
+  subscription (either pull or push) to a topic.
+"""
+
+from gcloud._helpers import get_default_project
+from gcloud._helpers import set_default_project
+from gcloud.connection import get_scoped_connection
+from gcloud.pubsub import _implicit_environ
+from gcloud.pubsub._implicit_environ import get_default_connection
+from gcloud.pubsub.connection import Connection
+
+
+SCOPE = ('https://www.googleapis.com/auth/pubsub',
+         'https://www.googleapis.com/auth/cloud-platform')
+
+
+def set_default_connection(connection=None):
+    """Set default connection either explicitly or implicitly as fall-back.
+
+    :type connection: :class:`gcloud.pubsub.connection.Connection`
+    :param connection: A connection provided to be the default.
+    """
+    _implicit_environ._DEFAULTS.connection = connection or get_connection()
+
+
+def set_defaults(project=None, connection=None):
+    """Set defaults either explicitly or implicitly as fall-back.
+
+    Uses the arguments to call the individual default methods.
+
+    :type project: string
+    :param project: Optional. The name of the project to connect to.
+
+    :type connection: :class:`gcloud.pubsub.connection.Connection`
+    :param connection: Optional. A connection provided to be the default.
+    """
+    set_default_project(project=project)
+    set_default_connection(connection=connection)
+
+
+def get_connection():
+    """Shortcut method to establish a connection to Cloud Storage.
+
+    Use this if you are going to access several buckets with the same
+    set of credentials:
+
+    >>> from gcloud import pubsub
+    >>> connection = pubsub.get_connection()
+    >>> bucket1 = pubsub.get_bucket('bucket1', connection=connection)
+    >>> bucket2 = pubsub.get_bucket('bucket2', connection=connection)
+
+    :rtype: :class:`gcloud.pubsub.connection.Connection`
+    :returns: A connection defined with the proper credentials.
+    """
+    return get_scoped_connection(Connection, SCOPE)
diff --git a/gcloud/pubsub/_implicit_environ.py b/gcloud/pubsub/_implicit_environ.py
new file mode 100644
index 000000000000..649b6f6528b8
--- /dev/null
+++ b/gcloud/pubsub/_implicit_environ.py
@@ -0,0 +1,41 @@
+# Copyright 2015 Google Inc. All rights reserved.
+#
+# 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.
+
+"""Module to provide implicit behavior based on enviroment.
+
+Allows the pubsub package to infer the default connection from the enviroment.
+"""
+
+
+class _DefaultsContainer(object):
+    """Container for defaults.
+
+    :type connection: :class:`gcloud.pubsub.connection.Connection`
+    :param connection: Persistent implied connection from environment.
+    """
+
+    def __init__(self, connection=None):
+        self.connection = connection
+
+
+def get_default_connection():
+    """Get default connection.
+
+    :rtype: :class:`gcloud.pubsub.connection.Connection` or ``NoneType``
+    :returns: The default connection if one has been set.
+    """
+    return _DEFAULTS.connection
+
+
+_DEFAULTS = _DefaultsContainer()
diff --git a/gcloud/pubsub/_testing.py b/gcloud/pubsub/_testing.py
new file mode 100644
index 000000000000..26a69ec95a3a
--- /dev/null
+++ b/gcloud/pubsub/_testing.py
@@ -0,0 +1,33 @@
+# Copyright 2014 Google Inc. All rights reserved.
+#
+# 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.
+
+"""Shared pubsub testing utilities."""
+
+from gcloud._testing import _Monkey
+from gcloud.pubsub import _implicit_environ
+from gcloud.pubsub._implicit_environ import _DefaultsContainer
+
+
+def _monkey_defaults(*args, **kwargs):
+    mock_defaults = _DefaultsContainer(*args, **kwargs)
+    return _Monkey(_implicit_environ, _DEFAULTS=mock_defaults)
+
+
+def _setup_defaults(test_case, *args, **kwargs):
+    test_case._replaced_defaults = _implicit_environ._DEFAULTS
+    _implicit_environ._DEFAULTS = _DefaultsContainer(*args, **kwargs)
+
+
+def _tear_down_defaults(test_case):
+    _implicit_environ._DEFAULTS = test_case._replaced_defaults
diff --git a/gcloud/pubsub/api.py b/gcloud/pubsub/api.py
index 32b11f1d286e..56f826ffecd9 100644
--- a/gcloud/pubsub/api.py
+++ b/gcloud/pubsub/api.py
@@ -14,6 +14,9 @@
 
 """ Define API functions (not bound to classes)."""
 
+from gcloud._helpers import get_default_project
+from gcloud.pubsub._implicit_environ import get_default_connection
+
 
 def list_topics(page_size=None, page_token=None,
                 project=None, connection=None):
@@ -45,6 +48,12 @@ def list_topics(page_size=None, page_token=None,
               more topics can be retrieved with another call (pass that
               value as ``page_token``).
     """
+    if project is None:
+        project = get_default_project()
+
+    if connection is None:
+        connection = get_default_connection()
+
     params = {}
 
     if page_size is not None:
@@ -93,6 +102,12 @@ def list_subscriptions(page_size=None, page_token=None, topic_name=None,
               more topics can be retrieved with another call (pass that
               value as ``page_token``).
     """
+    if project is None:
+        project = get_default_project()
+
+    if connection is None:
+        connection = get_default_connection()
+
     params = {}
 
     if page_size is not None:
diff --git a/gcloud/pubsub/test___init__.py b/gcloud/pubsub/test___init__.py
new file mode 100644
index 000000000000..19197c7105f3
--- /dev/null
+++ b/gcloud/pubsub/test___init__.py
@@ -0,0 +1,114 @@
+# Copyright 2015 Google Inc. All rights reserved.
+#
+# 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.
+
+import unittest2
+
+
+class Test_set_default_connection(unittest2.TestCase):
+
+    def setUp(self):
+        from gcloud.pubsub._testing import _setup_defaults
+        _setup_defaults(self)
+
+    def tearDown(self):
+        from gcloud.pubsub._testing import _tear_down_defaults
+        _tear_down_defaults(self)
+
+    def _callFUT(self, connection=None):
+        from gcloud.pubsub import set_default_connection
+        return set_default_connection(connection=connection)
+
+    def test_set_explicit(self):
+        from gcloud.pubsub import _implicit_environ
+
+        self.assertEqual(_implicit_environ.get_default_connection(), None)
+        fake_cnxn = object()
+        self._callFUT(connection=fake_cnxn)
+        self.assertEqual(_implicit_environ.get_default_connection(), fake_cnxn)
+
+    def test_set_implicit(self):
+        from gcloud._testing import _Monkey
+        from gcloud import pubsub
+        from gcloud.pubsub import _implicit_environ
+
+        self.assertEqual(_implicit_environ.get_default_connection(), None)
+
+        fake_cnxn = object()
+        _called_args = []
+        _called_kwargs = []
+
+        def mock_get_connection(*args, **kwargs):
+            _called_args.append(args)
+            _called_kwargs.append(kwargs)
+            return fake_cnxn
+
+        with _Monkey(pubsub, get_connection=mock_get_connection):
+            self._callFUT()
+
+        self.assertEqual(_implicit_environ.get_default_connection(), fake_cnxn)
+        self.assertEqual(_called_args, [()])
+        self.assertEqual(_called_kwargs, [{}])
+
+
+class Test_set_defaults(unittest2.TestCase):
+
+    def _callFUT(self, project=None, connection=None):
+        from gcloud.pubsub import set_defaults
+        return set_defaults(project=project, connection=connection)
+
+    def test_it(self):
+        from gcloud._testing import _Monkey
+        from gcloud import pubsub
+
+        PROJECT = object()
+        CONNECTION = object()
+
+        SET_PROJECT_CALLED = []
+
+        def call_set_project(project=None):
+            SET_PROJECT_CALLED.append(project)
+
+        SET_CONNECTION_CALLED = []
+
+        def call_set_connection(connection=None):
+            SET_CONNECTION_CALLED.append(connection)
+
+        with _Monkey(pubsub,
+                     set_default_connection=call_set_connection,
+                     set_default_project=call_set_project):
+            self._callFUT(project=PROJECT, connection=CONNECTION)
+
+        self.assertEqual(SET_PROJECT_CALLED, [PROJECT])
+        self.assertEqual(SET_CONNECTION_CALLED, [CONNECTION])
+
+
+class Test_get_connection(unittest2.TestCase):
+
+    def _callFUT(self, *args, **kw):
+        from gcloud.pubsub import get_connection
+        return get_connection(*args, **kw)
+
+    def test_it(self):
+        from gcloud import credentials
+        from gcloud.pubsub import SCOPE
+        from gcloud.pubsub.connection import Connection
+        from gcloud.test_credentials import _Client
+        from gcloud._testing import _Monkey
+        client = _Client()
+        with _Monkey(credentials, client=client):
+            found = self._callFUT()
+        self.assertTrue(isinstance(found, Connection))
+        self.assertTrue(found._credentials is client._signed)
+        self.assertEqual(found._credentials._scopes, SCOPE)
+        self.assertTrue(client._get_app_default_called)
diff --git a/gcloud/pubsub/test__implicit_environ.py b/gcloud/pubsub/test__implicit_environ.py
new file mode 100644
index 000000000000..9061c2bb6c89
--- /dev/null
+++ b/gcloud/pubsub/test__implicit_environ.py
@@ -0,0 +1,25 @@
+# Copyright 2014 Google Inc. All rights reserved.
+#
+# 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.
+
+import unittest2
+
+
+class Test_get_default_connection(unittest2.TestCase):
+
+    def _callFUT(self):
+        from gcloud.storage._implicit_environ import get_default_connection
+        return get_default_connection()
+
+    def test_wo_override(self):
+        self.assertTrue(self._callFUT() is None)
diff --git a/gcloud/pubsub/test_api.py b/gcloud/pubsub/test_api.py
index a244a5cd7392..430f6afbbe33 100644
--- a/gcloud/pubsub/test_api.py
+++ b/gcloud/pubsub/test_api.py
@@ -39,7 +39,29 @@ def test_w_explicit_connection_no_paging(self):
         self.assertEqual(req['path'], '/projects/%s/topics' % PROJECT)
         self.assertEqual(req['query_params'], {})
 
-    def test_w_explicit_connection_w_paging(self):
+    def test_w_implicit_connection_and_project_wo_paging(self):
+        from gcloud._testing import _monkey_defaults as _monkey_base_defaults
+        from gcloud.pubsub._testing import _monkey_defaults
+        TOPIC_NAME = 'topic_name'
+        PROJECT = 'PROJECT'
+        TOKEN = 'TOKEN'
+        returned = {'topics': [{'name': TOPIC_NAME}],
+                    'nextPageToken': TOKEN}
+        conn = _Connection(returned)
+        with _monkey_base_defaults(project=PROJECT):
+            with _monkey_defaults(connection=conn):
+                response = self._callFUT()
+        topics = response['topics']
+        self.assertEqual(len(topics), 1)
+        self.assertEqual(topics[0], {'name': TOPIC_NAME})
+        self.assertEqual(response['nextPageToken'], TOKEN)
+        self.assertEqual(len(conn._requested), 1)
+        req = conn._requested[0]
+        self.assertEqual(req['method'], 'GET')
+        self.assertEqual(req['path'], '/projects/%s/topics' % PROJECT)
+        self.assertEqual(req['query_params'], {})
+
+    def test_w_explicit_connection_and_project_w_paging(self):
         TOPIC_NAME = 'topic_name'
         PROJECT = 'PROJECT'
         TOKEN1 = 'TOKEN1'
@@ -67,7 +89,9 @@ def _callFUT(self, *args, **kw):
         from gcloud.pubsub.api import list_subscriptions
         return list_subscriptions(*args, **kw)
 
-    def test_w_explicit_connection_no_paging(self):
+    def test_w_implicit_connection_wo_paging(self):
+        from gcloud._testing import _monkey_defaults as _monkey_base_defaults
+        from gcloud.pubsub._testing import _monkey_defaults
         PROJECT = 'PROJECT'
         SUB_NAME = 'topic_name'
         SUB_PATH = 'projects/%s/subscriptions/%s' % (PROJECT, SUB_NAME)
@@ -77,7 +101,9 @@ def test_w_explicit_connection_no_paging(self):
         returned = {'subscriptions': [{'name': SUB_PATH, 'topic': TOPIC_PATH}],
                     'nextPageToken': TOKEN}
         conn = _Connection(returned)
-        response = self._callFUT(project=PROJECT, connection=conn)
+        with _monkey_base_defaults(project=PROJECT):
+            with _monkey_defaults(connection=conn):
+                response = self._callFUT()
         subscriptions = response['subscriptions']
         self.assertEqual(len(subscriptions), 1)
         self.assertEqual(subscriptions[0],
@@ -89,7 +115,7 @@ def test_w_explicit_connection_no_paging(self):
         self.assertEqual(req['path'], '/projects/%s/subscriptions' % PROJECT)
         self.assertEqual(req['query_params'], {})
 
-    def test_w_explicit_connection_w_paging(self):
+    def test_w_explicit_connection_and_project_w_paging(self):
         PROJECT = 'PROJECT'
         SUB_NAME = 'topic_name'
         SUB_PATH = 'projects/%s/subscriptions/%s' % (PROJECT, SUB_NAME)
diff --git a/gcloud/pubsub/test_topic.py b/gcloud/pubsub/test_topic.py
index 30a745ecda2c..a6d96ac96f50 100644
--- a/gcloud/pubsub/test_topic.py
+++ b/gcloud/pubsub/test_topic.py
@@ -25,11 +25,17 @@ def _makeOne(self, *args, **kw):
         return self._getTargetClass()(*args, **kw)
 
     def test_ctor_wo_inferred_project_or_connection(self):
+        from gcloud._testing import _monkey_defaults as _monkey_base_defaults
+        from gcloud.pubsub._testing import _monkey_defaults
         TOPIC_NAME = 'topic_name'
-        topic = self._makeOne(TOPIC_NAME)
+        PROJECT = 'PROJECT'
+        conn = _Connection()
+        with _monkey_base_defaults(project=PROJECT):
+            with _monkey_defaults(connection=conn):
+                topic = self._makeOne(TOPIC_NAME)
         self.assertEqual(topic.name, TOPIC_NAME)
-        self.assertEqual(topic.project, None)
-        self.assertEqual(topic.connection, None)
+        self.assertEqual(topic.project, PROJECT)
+        self.assertTrue(topic.connection is conn)
 
     def test_ctor_w_explicit_project_and_connection(self):
         TOPIC_NAME = 'topic_name'
diff --git a/gcloud/pubsub/topic.py b/gcloud/pubsub/topic.py
index 1d3b5eda246a..d9a7b9b16ecb 100644
--- a/gcloud/pubsub/topic.py
+++ b/gcloud/pubsub/topic.py
@@ -16,7 +16,9 @@
 
 import base64
 
+from gcloud._helpers import get_default_project
 from gcloud.exceptions import NotFound
+from gcloud.pubsub._implicit_environ import get_default_connection
 
 
 class Topic(object):
@@ -40,6 +42,10 @@ class Topic(object):
                         environment.
     """
     def __init__(self, name, project=None, connection=None):
+        if project is None:
+            project = get_default_project()
+        if connection is None:
+            connection = get_default_connection()
         self.name = name
         self.project = project
         self.connection = connection