diff --git a/taxii2client/common.py b/taxii2client/common.py
index cfd9d05..f8765d9 100644
--- a/taxii2client/common.py
+++ b/taxii2client/common.py
@@ -137,6 +137,15 @@ def _grab_total_items(resp):
         ), e)
 
 
+class TokenAuth(requests.auth.AuthBase):
+    def __init__(self, key):
+        self.key = key
+
+    def __call__(self, r):
+        r.headers['Authorization'] = 'Token {}'.format(self.key)
+        return r
+
+
 class _TAXIIEndpoint(object):
     """Contains some data and functionality common to all TAXII endpoint
     classes: a URL, connection, and ability to close the connection.  It also
@@ -145,7 +154,7 @@ class _TAXIIEndpoint(object):
 
     """
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None, version="2.0"):
+                 proxies=None, version="2.0", auth=None):
         """Create a TAXII endpoint.
 
         Args:
@@ -158,13 +167,13 @@ class _TAXIIEndpoint(object):
             version (str): The spec version this connection is meant to follow.
 
         """
-        if conn and (user or password):
-            raise InvalidArgumentsError("A connection and user/password may"
-                                        " not both be provided.")
+        if (conn and ((user or password) or auth)) or ((user or password) and auth):
+            raise InvalidArgumentsError("Only one of a connection, username/password, or auth object may"
+                                        " be provided.")
         elif conn:
             self._conn = conn
         else:
-            self._conn = _HTTPConnection(user, password, verify, proxies, version=version)
+            self._conn = _HTTPConnection(user, password, verify, proxies, version=version, auth=auth)
 
         # Add trailing slash to TAXII endpoint if missing
         # https://github.com/oasis-open/cti-taxii-client/issues/50
@@ -201,7 +210,7 @@ class _HTTPConnection(object):
     """
 
     def __init__(self, user=None, password=None, verify=True, proxies=None,
-                 user_agent=DEFAULT_USER_AGENT, version="2.0"):
+                 user_agent=DEFAULT_USER_AGENT, version="2.0", auth=None):
         """Create a connection session.
 
         Args:
@@ -219,8 +228,12 @@ class _HTTPConnection(object):
         self.session.verify = verify
         # enforce that we always have a connection-default user agent.
         self.user_agent = user_agent or DEFAULT_USER_AGENT
+
         if user and password:
             self.session.auth = requests.auth.HTTPBasicAuth(user, password)
+        elif auth:
+            self.session.auth = auth
+
         if proxies:
             self.session.proxies.update(proxies)
         self.version = version
diff --git a/taxii2client/v20/__init__.py b/taxii2client/v20/__init__.py
index 1df3a2d..f8421a8 100644
--- a/taxii2client/v20/__init__.py
+++ b/taxii2client/v20/__init__.py
@@ -62,7 +62,7 @@ class Status(_TAXIIEndpoint):
     # aren't other endpoints to call on the Status object.
 
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None, status_info=None):
+                 proxies=None, status_info=None, auth=None):
         """Create an API root resource endpoint.
 
         Args:
@@ -79,7 +79,7 @@ class Status(_TAXIIEndpoint):
                 (optional)
 
         """
-        super(Status, self).__init__(url, conn, user, password, verify, proxies)
+        super(Status, self).__init__(url, conn, user, password, verify, proxies, auth=auth)
         self.__raw = None
         if status_info:
             self._populate_fields(**status_info)
@@ -223,7 +223,7 @@ class Collection(_TAXIIEndpoint):
     """
 
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None, collection_info=None):
+                 proxies=None, collection_info=None, auth=None):
         """
         Initialize a new Collection.  Either user/password or conn may be
         given, but not both.  The latter is intended for internal use, when
@@ -247,7 +247,7 @@ class Collection(_TAXIIEndpoint):
 
         """
 
-        super(Collection, self).__init__(url, conn, user, password, verify, proxies)
+        super(Collection, self).__init__(url, conn, user, password, verify, proxies, auth=auth)
 
         self._loaded = False
         self.__raw = None
@@ -496,7 +496,7 @@ class ApiRoot(_TAXIIEndpoint):
     """
 
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None):
+                 proxies=None, auth=None):
         """Create an API root resource endpoint.
 
         Args:
@@ -510,7 +510,7 @@ class ApiRoot(_TAXIIEndpoint):
                 (optional)
 
         """
-        super(ApiRoot, self).__init__(url, conn, user, password, verify, proxies)
+        super(ApiRoot, self).__init__(url, conn, user, password, verify, proxies, auth=auth)
 
         self._loaded_collections = False
         self._loaded_information = False
@@ -639,7 +639,7 @@ class Server(_TAXIIEndpoint):
     """
 
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None):
+                 proxies=None, auth=None):
         """Create a server discovery endpoint.
 
         Args:
@@ -653,7 +653,7 @@ class Server(_TAXIIEndpoint):
                 (optional)
 
         """
-        super(Server, self).__init__(url, conn, user, password, verify, proxies)
+        super(Server, self).__init__(url, conn, user, password, verify, proxies, auth=auth)
 
         self._user = user
         self._password = password
@@ -661,6 +661,7 @@ class Server(_TAXIIEndpoint):
         self._proxies = proxies
         self._loaded = False
         self.__raw = None
+        self._auth = auth
 
     @property
     def title(self):
@@ -719,7 +720,8 @@ class Server(_TAXIIEndpoint):
                                    user=self._user,
                                    password=self._password,
                                    verify=self._verify,
-                                   proxies=self._proxies)
+                                   proxies=self._proxies,
+                                   auth=self._auth)
                            for url in roots]
         # If 'default' is one of the existing API Roots, reuse that object
         # rather than creating a duplicate. The TAXII 2.0 spec says that the
diff --git a/taxii2client/v21/__init__.py b/taxii2client/v21/__init__.py
index 0be971b..ccc1d7a 100644
--- a/taxii2client/v21/__init__.py
+++ b/taxii2client/v21/__init__.py
@@ -26,7 +26,7 @@ class Status(_TAXIIEndpoint):
     # aren't other endpoints to call on the Status object.
 
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None, status_info=None):
+                 proxies=None, status_info=None, auth=None):
         """Create an API root resource endpoint.
 
         Args:
@@ -43,7 +43,7 @@ class Status(_TAXIIEndpoint):
                 (optional)
 
         """
-        super(Status, self).__init__(url, conn, user, password, verify, proxies, "2.1")
+        super(Status, self).__init__(url, conn, user, password, verify, proxies, "2.1", auth=auth)
         self.__raw = None
         if status_info:
             self._populate_fields(**status_info)
@@ -186,7 +186,7 @@ class Collection(_TAXIIEndpoint):
     """
 
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None, collection_info=None):
+                 proxies=None, collection_info=None, auth=None):
         """
         Initialize a new Collection.  Either user/password or conn may be
         given, but not both.  The latter is intended for internal use, when
@@ -210,7 +210,7 @@ class Collection(_TAXIIEndpoint):
 
         """
 
-        super(Collection, self).__init__(url, conn, user, password, verify, proxies, "2.1")
+        super(Collection, self).__init__(url, conn, user, password, verify, proxies, "2.1", auth=auth)
 
         self._loaded = False
         self.__raw = None
@@ -461,7 +461,7 @@ class ApiRoot(_TAXIIEndpoint):
     """
 
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None):
+                 proxies=None, auth=None):
         """Create an API root resource endpoint.
 
         Args:
@@ -475,7 +475,7 @@ class ApiRoot(_TAXIIEndpoint):
                 (optional)
 
         """
-        super(ApiRoot, self).__init__(url, conn, user, password, verify, proxies, "2.1")
+        super(ApiRoot, self).__init__(url, conn, user, password, verify, proxies, "2.1", auth=auth)
 
         self._loaded_collections = False
         self._loaded_information = False
@@ -604,7 +604,7 @@ class Server(_TAXIIEndpoint):
     """
 
     def __init__(self, url, conn=None, user=None, password=None, verify=True,
-                 proxies=None):
+                 proxies=None, auth=None):
         """Create a server discovery endpoint.
 
         Args:
@@ -618,7 +618,7 @@ class Server(_TAXIIEndpoint):
                 (optional)
 
         """
-        super(Server, self).__init__(url, conn, user, password, verify, proxies, "2.1")
+        super(Server, self).__init__(url, conn, user, password, verify, proxies, "2.1", auth=auth)
 
         self._user = user
         self._password = password
@@ -626,6 +626,7 @@ class Server(_TAXIIEndpoint):
         self._proxies = proxies
         self._loaded = False
         self.__raw = None
+        self._auth = auth
 
     @property
     def title(self):
@@ -685,7 +686,8 @@ class Server(_TAXIIEndpoint):
                     user=self._user,
                     password=self._password,
                     verify=self._verify,
-                    proxies=self._proxies)
+                    proxies=self._proxies,
+                    auth=self._auth)
             for url in roots
         ]
         # If 'default' is one of the existing API Roots, reuse that object

diff --git a/taxii2client/test/test_client_v20.py b/taxii2client/test/test_client_v20.py
index c37d286..971a2bb 100644
--- a/taxii2client/test/test_client_v20.py
+++ b/taxii2client/test/test_client_v20.py
@@ -9,7 +9,7 @@ from taxii2client import (
     DEFAULT_USER_AGENT, MEDIA_TYPE_STIX_V20, MEDIA_TYPE_TAXII_V20
 )
 from taxii2client.common import (
-    _filter_kwargs_to_query_params, _HTTPConnection, _TAXIIEndpoint
+    TokenAuth, _filter_kwargs_to_query_params, _HTTPConnection, _TAXIIEndpoint
 )
 from taxii2client.exceptions import (
     AccessError, InvalidArgumentsError, InvalidJSONError,
@@ -714,11 +714,28 @@ def test_params_filter_unknown():
 def test_taxii_endpoint_raises_exception():
     """Test exception is raised when conn and (user or pass) is provided"""
     conn = _HTTPConnection(user="foo", password="bar", verify=False)
+    error_str = "Only one of a connection, username/password, or auth object may be provided."
+    fake_url = "https://example.com/api1/collections/"
 
     with pytest.raises(InvalidArgumentsError) as excinfo:
-        _TAXIIEndpoint("https://example.com/api1/collections/", conn, "other", "test")
+        _TAXIIEndpoint(fake_url, conn, "other", "test")
 
-    assert "A connection and user/password may not both be provided." in str(excinfo.value)
+    assert error_str in str(excinfo.value)
+
+    with pytest.raises(InvalidArgumentsError) as excinfo:
+        _TAXIIEndpoint(fake_url, conn, auth=TokenAuth('abcd'))
+
+    assert error_str in str(excinfo.value)
+
+    with pytest.raises(InvalidArgumentsError) as excinfo:
+        _TAXIIEndpoint(fake_url, user="other", password="test", auth=TokenAuth('abcd'))
+
+    assert error_str in str(excinfo.value)
+
+    with pytest.raises(InvalidArgumentsError) as excinfo:
+        _TAXIIEndpoint(fake_url, conn, "other", "test", auth=TokenAuth('abcd'))
+
+    assert error_str in str(excinfo.value)
 
 
 @responses.activate
diff --git a/taxii2client/test/test_client_v21.py b/taxii2client/test/test_client_v21.py
index b61df81..ff1e28e 100644
--- a/taxii2client/test/test_client_v21.py
+++ b/taxii2client/test/test_client_v21.py
@@ -7,7 +7,7 @@ import six
 
 from taxii2client import DEFAULT_USER_AGENT, MEDIA_TYPE_TAXII_V21
 from taxii2client.common import (
-    _filter_kwargs_to_query_params, _HTTPConnection, _TAXIIEndpoint
+    TokenAuth, _filter_kwargs_to_query_params, _HTTPConnection, _TAXIIEndpoint
 )
 from taxii2client.exceptions import (
     AccessError, InvalidArgumentsError, InvalidJSONError,
@@ -733,11 +733,28 @@ def test_params_filter_unknown():
 def test_taxii_endpoint_raises_exception():
     """Test exception is raised when conn and (user or pass) is provided"""
     conn = _HTTPConnection(user="foo", password="bar", verify=False)
+    error_str = "Only one of a connection, username/password, or auth object may be provided."
+    fake_url = "https://example.com/api1/collections/"
 
     with pytest.raises(InvalidArgumentsError) as excinfo:
-        _TAXIIEndpoint("https://example.com/api1/collections/", conn, "other", "test")
+        _TAXIIEndpoint(fake_url, conn, "other", "test")
 
-    assert "A connection and user/password may not both be provided." in str(excinfo.value)
+    assert error_str in str(excinfo.value)
+
+    with pytest.raises(InvalidArgumentsError) as excinfo:
+        _TAXIIEndpoint(fake_url, conn, auth=TokenAuth('abcd'))
+
+    assert error_str in str(excinfo.value)
+
+    with pytest.raises(InvalidArgumentsError) as excinfo:
+        _TAXIIEndpoint(fake_url, user="other", password="test", auth=TokenAuth('abcd'))
+
+    assert error_str in str(excinfo.value)
+
+    with pytest.raises(InvalidArgumentsError) as excinfo:
+        _TAXIIEndpoint(fake_url, conn, "other", "test", auth=TokenAuth('abcd'))
+
+    assert error_str in str(excinfo.value)
 
 
 @responses.activate

Question - why does the taxii client not implementing auth using api token?
I know of a few taxii servers requiring auth using api keys.
Is there any plan to implement auth using this?
e.g: `self.my_taxii = Server(url=self.url, verify=self.verify, proxies=self.proxies, token=self.api_key)`
taxii2client/test/test_client_v20.py::test_server_discovery taxii2client/test/test_client_v20.py::test_bad_json_response taxii2client/test/test_client_v20.py::test_minimal_discovery_response taxii2client/test/test_client_v20.py::test_discovery_with_no_default taxii2client/test/test_client_v20.py::test_discovery_with_no_title taxii2client/test/test_client_v20.py::test_api_root_no_title taxii2client/test/test_client_v20.py::test_api_root_no_versions taxii2client/test/test_client_v20.py::test_api_root_no_max_content_length taxii2client/test/test_client_v20.py::test_api_root taxii2client/test/test_client_v20.py::test_api_root_collections taxii2client/test/test_client_v20.py::test_collection taxii2client/test/test_client_v20.py::test_collection_unexpected_kwarg taxii2client/test/test_client_v20.py::test_get_collection_objects taxii2client/test/test_client_v20.py::test_get_object taxii2client/test/test_client_v20.py::test_cannot_write_to_readonly_collection taxii2client/test/test_client_v20.py::test_add_object_to_collection taxii2client/test/test_client_v20.py::test_add_object_to_collection_dict taxii2client/test/test_client_v20.py::test_add_object_to_collection_bin taxii2client/test/test_client_v20.py::test_add_object_to_collection_badtype taxii2client/test/test_client_v20.py::test_add_object_rases_error_when_collection_id_does_not_match_url taxii2client/test/test_client_v20.py::test_cannot_read_from_writeonly_collection taxii2client/test/test_client_v20.py::test_get_manifest taxii2client/test/test_client_v20.py::test_get_status taxii2client/test/test_client_v20.py::test_status_raw taxii2client/test/test_client_v20.py::test_content_type_valid taxii2client/test/test_client_v20.py::test_content_type_invalid taxii2client/test/test_client_v20.py::test_url_filter_type taxii2client/test/test_client_v20.py::test_filter_id taxii2client/test/test_client_v20.py::test_filter_version taxii2client/test/test_client_v20.py::test_filter_added_after taxii2client/test/test_client_v20.py::test_filter_combo taxii2client/test/test_client_v20.py::test_params_filter_unknown taxii2client/test/test_client_v20.py::test_taxii_endpoint_raises_exception taxii2client/test/test_client_v20.py::test_valid_content_type_for_connection taxii2client/test/test_client_v20.py::test_invalid_content_type_for_connection taxii2client/test/test_client_v20.py::test_status_missing_id_property taxii2client/test/test_client_v20.py::test_status_missing_status_property taxii2client/test/test_client_v20.py::test_status_missing_total_count_property taxii2client/test/test_client_v20.py::test_status_missing_success_count_property taxii2client/test/test_client_v20.py::test_status_missing_failure_count_property taxii2client/test/test_client_v20.py::test_status_missing_pending_count_property taxii2client/test/test_client_v20.py::test_collection_missing_id_property taxii2client/test/test_client_v20.py::test_collection_missing_title_property taxii2client/test/test_client_v20.py::test_collection_missing_can_read_property taxii2client/test/test_client_v20.py::test_collection_missing_can_write_property taxii2client/test/test_client_v20.py::test_conn_post_kwarg_errors taxii2client/test/test_client_v20.py::test_user_agent_defaulting taxii2client/test/test_client_v20.py::test_user_agent_overriding taxii2client/test/test_client_v20.py::test_user_agent_enforcing1 taxii2client/test/test_client_v20.py::test_user_agent_enforcing2 taxii2client/test/test_client_v20.py::test_user_agent_enforcing3 taxii2client/test/test_client_v20.py::test_header_merging taxii2client/test/test_client_v20.py::test_header_merge_none taxii2client/test/test_client_v20.py::test_collection_with_custom_properties taxii2client/test/test_client_v20.py::test_status_with_custom_properties taxii2client/test/test_client_v20.py::test_api_roots_with_custom_properties taxii2client/test/test_client_v20.py::test_server_with_custom_properties taxii2client/test/test_client_v20.py::test_collection_missing_trailing_slash taxii2client/test/test_client_v21.py::test_server_discovery taxii2client/test/test_client_v21.py::test_bad_json_response taxii2client/test/test_client_v21.py::test_minimal_discovery_response taxii2client/test/test_client_v21.py::test_discovery_with_no_default taxii2client/test/test_client_v21.py::test_discovery_with_no_title taxii2client/test/test_client_v21.py::test_api_root_no_title taxii2client/test/test_client_v21.py::test_api_root_no_versions taxii2client/test/test_client_v21.py::test_api_root_no_max_content_length taxii2client/test/test_client_v21.py::test_api_root taxii2client/test/test_client_v21.py::test_api_root_collections taxii2client/test/test_client_v21.py::test_collection taxii2client/test/test_client_v21.py::test_collection_unexpected_kwarg taxii2client/test/test_client_v21.py::test_get_collection_objects taxii2client/test/test_client_v21.py::test_get_object taxii2client/test/test_client_v21.py::test_cannot_write_to_readonly_collection taxii2client/test/test_client_v21.py::test_add_object_to_collection taxii2client/test/test_client_v21.py::test_add_object_to_collection_dict taxii2client/test/test_client_v21.py::test_add_object_to_collection_bin taxii2client/test/test_client_v21.py::test_add_object_to_collection_badtype taxii2client/test/test_client_v21.py::test_add_object_rases_error_when_collection_id_does_not_match_url taxii2client/test/test_client_v21.py::test_cannot_read_from_writeonly_collection taxii2client/test/test_client_v21.py::test_get_manifest taxii2client/test/test_client_v21.py::test_get_status taxii2client/test/test_client_v21.py::test_status_raw taxii2client/test/test_client_v21.py::test_content_type_valid taxii2client/test/test_client_v21.py::test_content_type_invalid taxii2client/test/test_client_v21.py::test_url_filter_type taxii2client/test/test_client_v21.py::test_filter_id taxii2client/test/test_client_v21.py::test_filter_version taxii2client/test/test_client_v21.py::test_filter_added_after taxii2client/test/test_client_v21.py::test_filter_combo taxii2client/test/test_client_v21.py::test_params_filter_unknown taxii2client/test/test_client_v21.py::test_taxii_endpoint_raises_exception taxii2client/test/test_client_v21.py::test_valid_content_type_for_connection taxii2client/test/test_client_v21.py::test_invalid_content_type_for_connection taxii2client/test/test_client_v21.py::test_status_missing_id_property taxii2client/test/test_client_v21.py::test_status_missing_status_property taxii2client/test/test_client_v21.py::test_status_missing_total_count_property taxii2client/test/test_client_v21.py::test_status_missing_success_count_property taxii2client/test/test_client_v21.py::test_status_missing_failure_count_property taxii2client/test/test_client_v21.py::test_status_missing_pending_count_property taxii2client/test/test_client_v21.py::test_collection_missing_id_property taxii2client/test/test_client_v21.py::test_collection_missing_title_property taxii2client/test/test_client_v21.py::test_collection_missing_can_read_property taxii2client/test/test_client_v21.py::test_collection_missing_can_write_property taxii2client/test/test_client_v21.py::test_conn_post_kwarg_errors taxii2client/test/test_client_v21.py::test_user_agent_defaulting taxii2client/test/test_client_v21.py::test_user_agent_overriding taxii2client/test/test_client_v21.py::test_user_agent_enforcing1 taxii2client/test/test_client_v21.py::test_user_agent_enforcing2 taxii2client/test/test_client_v21.py::test_user_agent_enforcing3 taxii2client/test/test_client_v21.py::test_header_merging taxii2client/test/test_client_v21.py::test_header_merge_none taxii2client/test/test_client_v21.py::test_collection_with_custom_properties taxii2client/test/test_client_v21.py::test_status_with_custom_properties taxii2client/test/test_client_v21.py::test_api_roots_with_custom_properties taxii2client/test/test_client_v21.py::test_server_with_custom_properties taxii2client/test/test_client_v21.py::test_collection_missing_trailing_slash