diff --git a/smart_open/http.py b/smart_open/http.py
index 7bbbe6f4..438ae0f4 100644
--- a/smart_open/http.py
+++ b/smart_open/http.py
@@ -50,7 +50,7 @@ def open_uri(uri, mode, transport_params):
 
 
 def open(uri, mode, kerberos=False, user=None, password=None, cert=None,
-         headers=None, timeout=None, buffer_size=DEFAULT_BUFFER_SIZE):
+         headers=None, timeout=None, session=None, buffer_size=DEFAULT_BUFFER_SIZE):
     """Implement streamed reader from a web site.
 
     Supports Kerberos and Basic HTTP authentication.
@@ -73,6 +73,9 @@ def open(uri, mode, kerberos=False, user=None, password=None, cert=None,
         Any headers to send in the request. If ``None``, the default headers are sent:
         ``{'Accept-Encoding': 'identity'}``. To use no headers at all,
         set this variable to an empty dict, ``{}``.
+    session: object, optional
+        The requests Session object to use with http get requests.
+        Can be used for OAuth2 clients.
     buffer_size: int, optional
         The buffer size to use when performing I/O.
 
@@ -86,7 +89,7 @@ def open(uri, mode, kerberos=False, user=None, password=None, cert=None,
         fobj = SeekableBufferedInputBase(
             uri, mode, buffer_size=buffer_size, kerberos=kerberos,
             user=user, password=password, cert=cert,
-            headers=headers, timeout=timeout,
+            headers=headers, session=session, timeout=timeout,
         )
         fobj.name = os.path.basename(urllib.parse.urlparse(uri).path)
         return fobj
@@ -97,7 +100,10 @@ def open(uri, mode, kerberos=False, user=None, password=None, cert=None,
 class BufferedInputBase(io.BufferedIOBase):
     def __init__(self, url, mode='r', buffer_size=DEFAULT_BUFFER_SIZE,
                  kerberos=False, user=None, password=None, cert=None,
-                 headers=None, timeout=None):
+                 headers=None, session=None, timeout=None):
+
+        self.session = session or requests
+
         if kerberos:
             import requests_kerberos
             auth = requests_kerberos.HTTPKerberosAuth()
@@ -116,7 +122,14 @@ def __init__(self, url, mode='r', buffer_size=DEFAULT_BUFFER_SIZE,
 
         self.timeout = timeout
 
-        self.response = requests.get(
+        self.response = session.get(
+            url,
+            auth=auth,
+            cert=cert,
+            stream=True,
+            headers=self.headers,
+            timeout=self.timeout,
+        ) if session is not None else requests.get(
             url,
             auth=auth,
             cert=cert,
@@ -217,7 +230,7 @@ class SeekableBufferedInputBase(BufferedInputBase):
 
     def __init__(self, url, mode='r', buffer_size=DEFAULT_BUFFER_SIZE,
                  kerberos=False, user=None, password=None, cert=None,
-                 headers=None, timeout=None):
+                 headers=None, session=None, timeout=None):
         """
         If Kerberos is True, will attempt to use the local Kerberos credentials.
         If cert is set, will try to use a client certificate
@@ -227,6 +240,8 @@ def __init__(self, url, mode='r', buffer_size=DEFAULT_BUFFER_SIZE,
         """
         self.url = url
 
+        self.session = session or requests
+
         if kerberos:
             import requests_kerberos
             self.auth = requests_kerberos.HTTPKerberosAuth()
@@ -332,7 +347,7 @@ def _partial_request(self, start_pos=None):
         if start_pos is not None:
             self.headers.update({"range": smart_open.utils.make_range_string(start_pos)})
 
-        response = requests.get(
+        response = self.session.get(
             self.url,
             auth=self.auth,
             stream=True,
diff --git a/smart_open/tests/test_http.py b/smart_open/tests/test_http.py
index 9433043f..a70f86d7 100644
--- a/smart_open/tests/test_http.py
+++ b/smart_open/tests/test_http.py
@@ -15,7 +15,7 @@
 import smart_open.http
 import smart_open.s3
 import smart_open.constants
-
+import requests
 
 BYTES = b'i tried so hard and got so far but in the end it doesn\'t even matter'
 URL = 'http://localhost'
@@ -159,6 +159,15 @@ def test_timeout_attribute(self):
         assert hasattr(reader, 'timeout')
         assert reader.timeout == timeout
 
+    @responses.activate
+    def test_session_attribute(self):
+        session = requests.Session()
+        responses.add_callback(responses.GET, URL, callback=request_callback)
+        reader = smart_open.open(URL, "rb", transport_params={'session': session})
+        assert hasattr(reader, 'session')
+        assert reader.session == session
+        assert reader.read() == BYTES
+
 
 @responses.activate
 def test_seek_implicitly_enabled(numbytes=10):