diff --git a/changelog.d/14403.misc b/changelog.d/14403.misc
new file mode 100644
index 000000000..ff28a2712
--- /dev/null
+++ b/changelog.d/14403.misc
@@ -0,0 +1 @@
+Faster joins: do not wait for full state when creating events to send.
diff --git a/synapse/events/builder.py b/synapse/events/builder.py
index e2ee10dd3..d62906043 100644
--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@@ -128,6 +128,7 @@ class EventBuilder:
                 state_filter=StateFilter.from_types(
                     auth_types_for_event(self.room_version, self)
                 ),
+                await_full_state=False,
             )
             auth_event_ids = self._event_auth_handler.compute_auth_events(
                 self, state_ids
diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index 6f3dd0463..833ffec3d 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -190,6 +190,7 @@ class StateHandler:
         room_id: str,
         event_ids: Collection[str],
         state_filter: Optional[StateFilter] = None,
+        await_full_state: bool = True,
     ) -> StateMap[str]:
         """Fetch the state after each of the given event IDs. Resolve them and return.
 
@@ -200,13 +201,18 @@ class StateHandler:
         Args:
             room_id: the room_id containing the given events.
             event_ids: the events whose state should be fetched and resolved.
+            await_full_state: if `True`, will block if we do not yet have complete state
+                at the given `event_id`s, regardless of whether `state_filter` is
+                satisfied by partial state.
 
         Returns:
             the state dict (a mapping from (event_type, state_key) -> event_id) which
             holds the resolution of the states after the given event IDs.
         """
         logger.debug("calling resolve_state_groups from compute_state_after_events")
-        ret = await self.resolve_state_groups_for_events(room_id, event_ids)
+        ret = await self.resolve_state_groups_for_events(
+            room_id, event_ids, await_full_state
+        )
         return await ret.get_state(self._state_storage_controller, state_filter)
 
     async def get_current_user_ids_in_room(