diff --git a/changelog.d/5856.feature b/changelog.d/5856.feature
new file mode 100644
index 0000000000..f4310b9244
--- /dev/null
+++ b/changelog.d/5856.feature
@@ -0,0 +1 @@
+Add a tag recording a request's authenticated entity and corresponding servlet in opentracing.
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 179644852a..7b3a5a8221 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -22,6 +22,7 @@ from netaddr import IPAddress
 
 from twisted.internet import defer
 
+import synapse.logging.opentracing as opentracing
 import synapse.types
 from synapse import event_auth
 from synapse.api.constants import EventTypes, JoinRules, Membership
@@ -178,6 +179,7 @@ class Auth(object):
     def get_public_keys(self, invite_event):
         return event_auth.get_public_keys(invite_event)
 
+    @opentracing.trace
     @defer.inlineCallbacks
     def get_user_by_req(
         self, request, allow_guest=False, rights="access", allow_expired=False
@@ -209,6 +211,7 @@ class Auth(object):
             user_id, app_service = yield self._get_appservice_user_id(request)
             if user_id:
                 request.authenticated_entity = user_id
+                opentracing.set_tag("authenticated_entity", user_id)
 
                 if ip_addr and self.hs.config.track_appservice_user_ips:
                     yield self.store.insert_client_ip(
@@ -259,6 +262,7 @@ class Auth(object):
                 )
 
             request.authenticated_entity = user.to_string()
+            opentracing.set_tag("authenticated_entity", user.to_string())
 
             return synapse.types.create_requester(
                 user, token_id, is_guest, device_id, app_service=app_service
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 9a86bd0263..a17148fc3c 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -22,7 +22,6 @@ import re
 from twisted.internet.defer import maybeDeferred
 
 import synapse
-import synapse.logging.opentracing as opentracing
 from synapse.api.errors import Codes, FederationDeniedError, SynapseError
 from synapse.api.room_versions import RoomVersions
 from synapse.api.urls import (
@@ -39,6 +38,7 @@ from synapse.http.servlet import (
     parse_string_from_args,
 )
 from synapse.logging.context import run_in_background
+from synapse.logging.opentracing import start_active_span_from_context, tags
 from synapse.types import ThirdPartyInstanceID, get_domain_from_id
 from synapse.util.ratelimitutils import FederationRateLimiter
 from synapse.util.versionstring import get_version_string
@@ -289,16 +289,17 @@ class BaseFederationServlet(object):
                 raise
 
             # Start an opentracing span
-            with opentracing.start_active_span_from_context(
+            with start_active_span_from_context(
                 request.requestHeaders,
                 "incoming-federation-request",
                 tags={
                     "request_id": request.get_request_id(),
-                    opentracing.tags.SPAN_KIND: opentracing.tags.SPAN_KIND_RPC_SERVER,
-                    opentracing.tags.HTTP_METHOD: request.get_method(),
-                    opentracing.tags.HTTP_URL: request.get_redacted_uri(),
-                    opentracing.tags.PEER_HOST_IPV6: request.getClientIP(),
+                    tags.SPAN_KIND: tags.SPAN_KIND_RPC_SERVER,
+                    tags.HTTP_METHOD: request.get_method(),
+                    tags.HTTP_URL: request.get_redacted_uri(),
+                    tags.PEER_HOST_IPV6: request.getClientIP(),
                     "authenticated_entity": origin,
+                    "servlet_name": request.request_metrics.name,
                 },
             ):
                 if origin:
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index d07d356464..4326e98a28 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -36,7 +36,6 @@ from twisted.internet.task import _EPSILON, Cooperator
 from twisted.web._newclient import ResponseDone
 from twisted.web.http_headers import Headers
 
-import synapse.logging.opentracing as opentracing
 import synapse.metrics
 import synapse.util.retryutils
 from synapse.api.errors import (
@@ -50,6 +49,12 @@ from synapse.http import QuieterFileBodyProducer
 from synapse.http.client import BlacklistingAgentWrapper, IPBlacklistingResolver
 from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent
 from synapse.logging.context import make_deferred_yieldable
+from synapse.logging.opentracing import (
+    inject_active_span_byte_dict,
+    set_tag,
+    start_active_span,
+    tags,
+)
 from synapse.util.async_helpers import timeout_deferred
 from synapse.util.metrics import Measure
 
@@ -341,20 +346,20 @@ class MatrixFederationHttpClient(object):
             query_bytes = b""
 
         # Retreive current span
-        scope = opentracing.start_active_span(
+        scope = start_active_span(
             "outgoing-federation-request",
             tags={
-                opentracing.tags.SPAN_KIND: opentracing.tags.SPAN_KIND_RPC_CLIENT,
-                opentracing.tags.PEER_ADDRESS: request.destination,
-                opentracing.tags.HTTP_METHOD: request.method,
-                opentracing.tags.HTTP_URL: request.path,
+                tags.SPAN_KIND: tags.SPAN_KIND_RPC_CLIENT,
+                tags.PEER_ADDRESS: request.destination,
+                tags.HTTP_METHOD: request.method,
+                tags.HTTP_URL: request.path,
             },
             finish_on_close=True,
         )
 
         # Inject the span into the headers
         headers_dict = {}
-        opentracing.inject_active_span_byte_dict(headers_dict, request.destination)
+        inject_active_span_byte_dict(headers_dict, request.destination)
 
         headers_dict[b"User-Agent"] = [self.version_string_bytes]
 
@@ -436,9 +441,7 @@ class MatrixFederationHttpClient(object):
                         response.phrase.decode("ascii", errors="replace"),
                     )
 
-                    opentracing.set_tag(
-                        opentracing.tags.HTTP_STATUS_CODE, response.code
-                    )
+                    set_tag(tags.HTTP_STATUS_CODE, response.code)
 
                     if 200 <= response.code < 300:
                         pass