diff --git a/exchangelib/__init__.py b/exchangelib/__init__.py
index cecb108..026f841 100644
--- a/exchangelib/__init__.py
+++ b/exchangelib/__init__.py
@@ -12,6 +12,7 @@
 from .items import AcceptItem, TentativelyAcceptItem, DeclineItem, CalendarItem, CancelCalendarItem, Contact, \
     DistributionList, Message, PostItem, Task
 from .properties import Body, HTMLBody, ItemId, Mailbox, Attendee, Room, RoomList, UID
+from .protocol import BaseProtocol
 from .restriction import Q
 from .transport import BASIC, DIGEST, NTLM, GSSAPI
 from .version import Build, Version
@@ -38,6 +39,9 @@
     'Build', 'Version',
 ]
 
+# Set a default user agent, e.g. "exchangelib/3.1.1"
+BaseProtocol.USERAGENT = "%s/%s (%s)" % (__name__, __version__)
+
 
 def close_connections():
     from .autodiscover import close_connections as close_autodiscover_connections
diff --git a/exchangelib/protocol.py b/exchangelib/protocol.py
index cdffe94..abbd51e 100644
--- a/exchangelib/protocol.py
+++ b/exchangelib/protocol.py
@@ -48,6 +48,8 @@ class BaseProtocol(object):
     CONNECTIONS_PER_SESSION = 1
     # Timeout for HTTP requests
     TIMEOUT = 120
+    # The User-Agent header to use for HTTP requests. Override this to set an app-specific one
+    USERAGENT = None
 
     # The adapter class to use for HTTP requests. Override this if you need e.g. proxy support or specific TLS versions
     HTTP_ADAPTER_CLS = requests.adapters.HTTPAdapter
@@ -133,6 +135,7 @@ def create_session(self):
         session.auth = get_auth_instance(credentials=self.credentials, auth_type=self.auth_type)
         # Create a copy of the headers because headers are mutable and session users may modify headers
         session.headers.update(DEFAULT_HEADERS.copy())
+        session.headers['User-Agent'] = self.USERAGENT
         session.mount('http://', adapter=self.get_adapter())
         session.mount('https://', adapter=self.get_adapter())
         log.debug('Server %s: Created session %s', self.server, session.session_id)