diff --git a/synapse/appservice/scheduler.py b/synapse/appservice/scheduler.py
index 3aff89d38cdf..acd2b3558dce 100644
--- a/synapse/appservice/scheduler.py
+++ b/synapse/appservice/scheduler.py
@@ -59,7 +59,12 @@
 
 logger = logging.getLogger(__name__)
 
-MAX_EVENTS_PER_TRANSACTION = 100
+
+# Maximum number of events to provide in a AS transaction.
+MAX_PERSISTENT_EVENTS_PER_TRANSACTION = 100
+
+# Maximum number of ephemeral events to provide in a AS transaction.
+MAX_EPHEMERAL_EVENTS_PER_TRANSACTION = 100
 
 
 class ApplicationServiceScheduler:
@@ -139,12 +144,12 @@ async def _send_request(self, service: ApplicationService):
         try:
             while True:
                 all_events = self.queued_events.get(service.id, [])
-                events = all_events[:MAX_EVENTS_PER_TRANSACTION]
-                del all_events[MAX_EVENTS_PER_TRANSACTION:]
+                events = all_events[:MAX_PERSISTENT_EVENTS_PER_TRANSACTION]
+                del all_events[:MAX_PERSISTENT_EVENTS_PER_TRANSACTION]
 
                 all_events_ephemeral = self.queued_ephemeral.get(service.id, [])
-                ephemeral = all_events_ephemeral[:MAX_EVENTS_PER_TRANSACTION]
-                del all_events_ephemeral[MAX_EVENTS_PER_TRANSACTION:]
+                ephemeral = all_events_ephemeral[:MAX_EPHEMERAL_EVENTS_PER_TRANSACTION]
+                del all_events_ephemeral[:MAX_EPHEMERAL_EVENTS_PER_TRANSACTION]
 
                 if not events and not ephemeral:
                     return
diff --git a/tests/appservice/test_scheduler.py b/tests/appservice/test_scheduler.py
index 2acb8b7603b0..97f8cad0ddd4 100644
--- a/tests/appservice/test_scheduler.py
+++ b/tests/appservice/test_scheduler.py
@@ -260,6 +260,31 @@ def do_send(x, y, z):
         self.txn_ctrl.send.assert_called_with(srv2, [srv_2_event2], [])
         self.assertEquals(3, self.txn_ctrl.send.call_count)
 
+    def test_send_large_txns(self):
+        srv_1_defer = defer.Deferred()
+        srv_2_defer = defer.Deferred()
+        send_return_list = [srv_1_defer, srv_2_defer]
+
+        def do_send(x, y, z):
+            return make_deferred_yieldable(send_return_list.pop(0))
+
+        self.txn_ctrl.send = Mock(side_effect=do_send)
+
+        service = Mock(id=4, name="service")
+        event_list = [Mock(name="event%i" % (i + 1)) for i in range(200)]
+        for event in event_list:
+            self.queuer.enqueue_event(service, event)
+
+        # Expect the first event to be sent immediately.
+        self.txn_ctrl.send.assert_called_with(service, [event_list[0]], [])
+        srv_1_defer.callback(service)
+        # Then send the next 100 events
+        self.txn_ctrl.send.assert_called_with(service, event_list[1:101], [])
+        srv_2_defer.callback(service)
+        # Then the final 99 events
+        self.txn_ctrl.send.assert_called_with(service, event_list[101:], [])
+        self.assertEquals(3, self.txn_ctrl.send.call_count)
+
     def test_send_single_ephemeral_no_queue(self):
         # Expect the event to be sent immediately.
         service = Mock(id=4, name="service")
@@ -296,3 +321,19 @@ def test_send_single_ephemeral_with_queue(self):
         # Expect the queued events to be sent
         self.txn_ctrl.send.assert_called_with(service, [], event_list_2 + event_list_3)
         self.assertEquals(2, self.txn_ctrl.send.call_count)
+
+    def test_send_large_txns_ephemeral(self):
+        d = defer.Deferred()
+        self.txn_ctrl.send = Mock(
+            side_effect=lambda x, y, z: make_deferred_yieldable(d)
+        )
+        # Expect the event to be sent immediately.
+        service = Mock(id=4, name="service")
+        first_chunk = [Mock(name="event%i" % (i + 1)) for i in range(100)]
+        second_chunk = [Mock(name="event%i" % (i + 101)) for i in range(50)]
+        event_list = first_chunk + second_chunk
+        self.queuer.enqueue_ephemeral(service, event_list)
+        self.txn_ctrl.send.assert_called_once_with(service, [], first_chunk)
+        d.callback(service)
+        self.txn_ctrl.send.assert_called_with(service, [], second_chunk)
+        self.assertEquals(2, self.txn_ctrl.send.call_count)