diff --git a/keystoneauth1/session.py b/keystoneauth1/session.py
index 60f712e6..d5938066 100644
--- a/keystoneauth1/session.py
+++ b/keystoneauth1/session.py
@@ -52,6 +52,10 @@ _LOG_CONTENT_TYPES = set(['application/json'])
 
 _MAX_RETRY_INTERVAL = 60.0
 
+# NOTE(efried): This is defined in oslo_middleware.request_id.INBOUND_HEADER,
+# but it didn't seem worth adding oslo_middleware to requirements just for that
+_REQUEST_ID_HEADER = 'X-Openstack-Request-Id'
+
 
 def _construct_session(session_obj=None):
     # NOTE(morganfainberg): if the logic in this function changes be sure to
@@ -579,7 +583,7 @@ class Session(object):
                 allow=None, client_name=None, client_version=None,
                 microversion=None, microversion_service_type=None,
                 status_code_retries=0, retriable_status_codes=None,
-                rate_semaphore=None, **kwargs):
+                rate_semaphore=None, global_request_id=None, **kwargs):
         """Send an HTTP request with the specified characteristics.
 
         Wrapper around `requests.Session.request` to handle tasks such as
@@ -668,6 +672,7 @@ class Session(object):
         :param rate_semaphore: Semaphore to be used to control concurrency
                                and rate limiting of requests. (optional,
                                defaults to no concurrency or rate control)
+        :param global_request_id: Value for the X-Openstack-Request-Id header.
         :param kwargs: any other parameter that can be passed to
                        :meth:`requests.Session.request` (such as `headers`).
                        Except:
@@ -785,6 +790,12 @@ class Session(object):
             headers.setdefault('Content-Type', 'application/json')
             kwargs['data'] = self._json.encode(json)
 
+        if global_request_id is not None:
+            # NOTE(efried): This does *not* setdefault. If a global_request_id
+            # kwarg was explicitly specified, it should override any value
+            # previously configured (e.g. in Adapter.global_request_id).
+            headers[_REQUEST_ID_HEADER] = global_request_id
+
         for k, v in self.additional_headers.items():
             headers.setdefault(k, v)
 
diff --git a/keystoneauth1/tests/unit/test_session.py b/keystoneauth1/tests/unit/test_session.py
index d67f5ab2..59846943 100644
--- a/keystoneauth1/tests/unit/test_session.py
+++ b/keystoneauth1/tests/unit/test_session.py
@@ -1296,19 +1296,25 @@ class AdapterTest(utils.TestCase):
         self.assertRequestHeaderEqual('User-Agent', self.USER_AGENT)
 
     def test_setting_global_id_on_request(self):
-        global_id = "req-%s" % uuid.uuid4()
+        global_id_adpt = "req-%s" % uuid.uuid4()
+        global_id_req = "req-%s" % uuid.uuid4()
         response = uuid.uuid4().hex
         self.stub_url('GET', text=response)
-        adpt = adapter.Adapter(client_session.Session(),
-                               auth=CalledAuthPlugin(),
-                               service_type=self.SERVICE_TYPE,
-                               service_name=self.SERVICE_NAME,
-                               interface=self.INTERFACE,
-                               region_name=self.REGION_NAME,
-                               user_agent=self.USER_AGENT,
-                               version=self.VERSION,
-                               allow=self.ALLOW,
-                               global_request_id=global_id)
+
+        def mk_adpt(**kwargs):
+            return adapter.Adapter(client_session.Session(),
+                                   auth=CalledAuthPlugin(),
+                                   service_type=self.SERVICE_TYPE,
+                                   service_name=self.SERVICE_NAME,
+                                   interface=self.INTERFACE,
+                                   region_name=self.REGION_NAME,
+                                   user_agent=self.USER_AGENT,
+                                   version=self.VERSION,
+                                   allow=self.ALLOW,
+                                   **kwargs)
+
+        # No global_request_id
+        adpt = mk_adpt()
         resp = adpt.get('/')
         self.assertEqual(resp.text, response)
 
@@ -1316,7 +1322,21 @@ class AdapterTest(utils.TestCase):
         self.assertEqual(self.ALLOW,
                          adpt.auth.endpoint_arguments['allow'])
         self.assertTrue(adpt.auth.get_token_called)
-        self.assertRequestHeaderEqual('X-OpenStack-Request-ID', global_id)
+        self.assertRequestHeaderEqual('X-OpenStack-Request-ID', None)
+
+        # global_request_id only on the request
+        adpt.get('/', global_request_id=global_id_req)
+        self.assertRequestHeaderEqual('X-OpenStack-Request-ID', global_id_req)
+
+        # global_request_id only on the adapter
+        adpt = mk_adpt(global_request_id=global_id_adpt)
+        adpt.get('/')
+        self.assertRequestHeaderEqual('X-OpenStack-Request-ID', global_id_adpt)
+
+        # global_request_id on the adapter *and* the request (the request takes
+        # precedence)
+        adpt.get('/', global_request_id=global_id_req)
+        self.assertRequestHeaderEqual('X-OpenStack-Request-ID', global_id_req)
 
     def test_setting_variables_on_get_endpoint(self):
         adpt = self._create_loaded_adapter()