diff --git a/synapse/storage/state.py b/synapse/storage/state.py
new file mode 100644
index 000000000..b910646d7
--- /dev/null
+++ b/synapse/storage/state.py
@@ -0,0 +1,97 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ._base import SQLBaseStore
+from twisted.internet import defer
+
+from collections import namedtuple
+
+
+StateGroup = namedtuple("StateGroup", ("group", "state"))
+
+
+class StateStore(SQLBaseStore):
+
+    @defer.inlineCallbacks
+    def get_state_groups(self, event_ids):
+        groups = set()
+        for event_id in event_ids:
+            group = yield self._simple_select_one_onecol(
+                table="event_to_state_groups",
+                keyvalues={"event_id": event_id},
+                retcol="state_group",
+                allow_none=True,
+            )
+            if group:
+                groups.add(group)
+
+        res = []
+        for group in groups:
+            state_ids = yield self._simple_select_onecol(
+                table="state_groups_state",
+                keyvalues={"state_group": group},
+                retcol="event_id",
+            )
+            state = []
+            for state_id in state_ids:
+                s = yield self.get_event(
+                    state_id,
+                    allow_none=True,
+                )
+                if s:
+                    state.append(s)
+
+            res.append(StateGroup(group, state))
+
+        defer.returnValue(res)
+
+    def store_state_groups(self, event):
+        return self.runInteraction(
+            self._store_state_groups_txn, event
+        )
+
+    def _store_state_groups_txn(self, txn, event):
+        state_group = event.state_group
+        if not state_group:
+            state_group = self._simple_insert_txn(
+                txn,
+                table="state_groups",
+                values={
+                    "room_id": event.room_id,
+                    "event_id": event.event_id,
+                }
+            )
+
+            for state in event.state_events:
+                self._simple_insert_txn(
+                    txn,
+                    table="state_groups_state",
+                    values={
+                        "state_group": state_group,
+                        "room_id": state.room_id,
+                        "type": state.type,
+                        "state_key": state.state_key,
+                        "event_id": state.event_id,
+                    }
+                )
+
+        self._simple_insert_txn(
+            txn,
+            table="event_to_state_groups",
+            values={
+                "state_group": state_group,
+                "event_id": event.event_id,
+            }
+        )