diff --git a/changelog.d/20302.bugfix b/changelog.d/20302.bugfix
new file mode 100644
index 0000000000..f563c2959d
--- /dev/null
+++ b/changelog.d/20302.bugfix
@@ -0,0 +1 @@
+Set up `un_partial_stated_room_stream_sequence` during SQLite -> PostgreSQL DB porting, preventing a PostgreSQL sequence inconsistency error on startup.
diff --git a/synapse/_scripts/synapse_port_db.py b/synapse/_scripts/synapse_port_db.py
index f4f598d27c..495d61aedb 100755
--- a/synapse/_scripts/synapse_port_db.py
+++ b/synapse/_scripts/synapse_port_db.py
@@ -833,6 +833,10 @@ class Porter:
                 "un_partial_stated_event_stream_sequence",
                 [("un_partial_stated_event_stream", "stream_id")],
             )
+            await self._setup_sequence(
+                "un_partial_stated_room_stream_sequence",
+                [("un_partial_stated_room_stream", "stream_id")],
+            )
             await self._setup_sequence(
                 "device_inbox_sequence",
                 [