diff --git a/keystoneauth1/adapter.py b/keystoneauth1/adapter.py
index 8d438f37..c23d9a39 100644
--- a/keystoneauth1/adapter.py
+++ b/keystoneauth1/adapter.py
@@ -13,6 +13,8 @@
 import os
 import warnings
 
+import requests
+
 from keystoneauth1 import _fair_semaphore
 from keystoneauth1 import session
 
@@ -198,7 +200,14 @@ class Adapter(object):
     def request(self, url, method, **kwargs):
         endpoint_filter = kwargs.setdefault('endpoint_filter', {})
         self._set_endpoint_filter_kwargs(endpoint_filter)
-
+        # NOTE(gmann): Convert r initlize the headers to
+        # CaseInsensitiveDict to make sure headers are
+        # case insensitive.
+        if kwargs.get('headers'):
+            kwargs['headers'] = requests.structures.CaseInsensitiveDict(
+                kwargs['headers'])
+        else:
+            kwargs['headers'] = requests.structures.CaseInsensitiveDict()
         if self.endpoint_override:
             kwargs.setdefault('endpoint_override', self.endpoint_override)
 
diff --git a/keystoneauth1/session.py b/keystoneauth1/session.py
index 935e022f..f4c400c0 100644
--- a/keystoneauth1/session.py
+++ b/keystoneauth1/session.py
@@ -753,6 +753,14 @@ class Session(object):
         else:
             split_loggers = None
         logger = logger or utils.get_logger(__name__)
+        # NOTE(gmann): Convert r initlize the headers to
+        # CaseInsensitiveDict to make sure headers are
+        # case insensitive.
+        if kwargs.get('headers'):
+            kwargs['headers'] = requests.structures.CaseInsensitiveDict(
+                kwargs['headers'])
+        else:
+            kwargs['headers'] = requests.structures.CaseInsensitiveDict()
         if connect_retries is None:
             connect_retries = self._connect_retries
         # HTTP 503 - Service Unavailable
diff --git a/keystoneauth1/tests/unit/test_session.py b/keystoneauth1/tests/unit/test_session.py
index 8817e4e7..3ded3f5c 100644
--- a/keystoneauth1/tests/unit/test_session.py
+++ b/keystoneauth1/tests/unit/test_session.py
@@ -1822,7 +1822,7 @@ class AdapterTest(utils.TestCase):
             with mock.patch.object(sess, 'request') as m:
                 adapter.Adapter(sess, **adap_kwargs).get(url, **get_kwargs)
                 m.assert_called_once_with(url, 'GET', endpoint_filter={},
-                                          rate_semaphore=mock.ANY,
+                                          headers={}, rate_semaphore=mock.ANY,
                                           **exp_kwargs)
 
         # No default_microversion in Adapter, no microversion in get()
@@ -1846,7 +1846,7 @@ class AdapterTest(utils.TestCase):
             with mock.patch.object(sess, 'request') as m:
                 adapter.Adapter(sess, **adap_kwargs).get(url, **get_kwargs)
                 m.assert_called_once_with(url, 'GET', endpoint_filter={},
-                                          rate_semaphore=mock.ANY,
+                                          headers={}, rate_semaphore=mock.ANY,
                                           **exp_kwargs)
 
         # No raise_exc in Adapter or get()