diff --git a/clientapi/routing/routing.go b/clientapi/routing/routing.go
index e7b9a8500..39eee8210 100644
--- a/clientapi/routing/routing.go
+++ b/clientapi/routing/routing.go
@@ -585,6 +585,7 @@ func Setup(
 			}
 			return *SearchUserDirectory(
 				req.Context(),
+				device,
 				userAPI,
 				stateAPI,
 				cfg.Matrix.ServerName,
diff --git a/clientapi/routing/userdirectory.go b/clientapi/routing/userdirectory.go
index 774b0e96e..db81ffeae 100644
--- a/clientapi/routing/userdirectory.go
+++ b/clientapi/routing/userdirectory.go
@@ -32,6 +32,7 @@ type UserDirectoryResponse struct {
 
 func SearchUserDirectory(
 	ctx context.Context,
+	device *userapi.Device,
 	userAPI userapi.UserInternalAPI,
 	stateAPI currentstateAPI.CurrentStateInternalAPI,
 	serverName gomatrixserverlib.ServerName,
@@ -81,6 +82,7 @@ func SearchUserDirectory(
 
 	if len(results) <= limit {
 		stateReq := &currentstateAPI.QueryKnownUsersRequest{
+			UserID:       device.UserID,
 			SearchString: searchString,
 			Limit:        limit - len(results),
 		}
diff --git a/currentstateserver/api/api.go b/currentstateserver/api/api.go
index c4f4d8357..4ebe29683 100644
--- a/currentstateserver/api/api.go
+++ b/currentstateserver/api/api.go
@@ -92,6 +92,7 @@ type QueryCurrentStateResponse struct {
 }
 
 type QueryKnownUsersRequest struct {
+	UserID       string `json:"user_id"`
 	SearchString string `json:"search_string"`
 	Limit        int    `json:"limit"`
 }
diff --git a/currentstateserver/internal/api.go b/currentstateserver/internal/api.go
index ff4093034..dc2554121 100644
--- a/currentstateserver/internal/api.go
+++ b/currentstateserver/internal/api.go
@@ -51,7 +51,7 @@ func (a *CurrentStateInternalAPI) QueryRoomsForUser(ctx context.Context, req *ap
 }
 
 func (a *CurrentStateInternalAPI) QueryKnownUsers(ctx context.Context, req *api.QueryKnownUsersRequest, res *api.QueryKnownUsersResponse) error {
-	users, err := a.DB.GetKnownUsers(ctx, req.SearchString, req.Limit)
+	users, err := a.DB.GetKnownUsers(ctx, req.UserID, req.SearchString, req.Limit)
 	if err != nil {
 		return err
 	}
diff --git a/currentstateserver/storage/interface.go b/currentstateserver/storage/interface.go
index 81b73ee40..5a754b9ea 100644
--- a/currentstateserver/storage/interface.go
+++ b/currentstateserver/storage/interface.go
@@ -39,6 +39,6 @@ type Database interface {
 	RedactEvent(ctx context.Context, redactedEventID string, redactedBecause gomatrixserverlib.HeaderedEvent) error
 	// JoinedUsersSetInRooms returns all joined users in the rooms given, along with the count of how many times they appear.
 	JoinedUsersSetInRooms(ctx context.Context, roomIDs []string) (map[string]int, error)
-	// GetKnownUsers searches all users that we know about.
-	GetKnownUsers(ctx context.Context, searchString string, limit int) ([]string, error)
+	// GetKnownUsers searches all users that userID knows about.
+	GetKnownUsers(ctx context.Context, userID, searchString string, limit int) ([]string, error)
 }
diff --git a/currentstateserver/storage/postgres/current_room_state_table.go b/currentstateserver/storage/postgres/current_room_state_table.go
index e95f96119..c5414e449 100644
--- a/currentstateserver/storage/postgres/current_room_state_table.go
+++ b/currentstateserver/storage/postgres/current_room_state_table.go
@@ -83,7 +83,9 @@ const selectJoinedUsersSetForRoomsSQL = "" +
 	" type = 'm.room.member' and content_value = 'join' GROUP BY state_key"
 
 const selectKnownUsersSQL = "" +
-	"SELECT DISTINCT state_key FROM currentstate_current_room_state WHERE type = 'm.room.member' AND state_key LIKE $1 LIMIT $2"
+	"SELECT DISTINCT state_key FROM currentstate_current_room_state WHERE room_id = ANY(" +
+	"  SELECT DISTINCT room_id FROM currentstate_current_room_state WHERE state_key=$1 AND TYPE='m.room.member' AND content_value='join'" +
+	") AND TYPE='m.room.member' AND content_value='join' AND state_key LIKE $2 LIMIT $3"
 
 type currentRoomStateStatements struct {
 	upsertRoomStateStmt              *sql.Stmt
@@ -304,8 +306,8 @@ func (s *currentRoomStateStatements) SelectBulkStateContent(
 	return strippedEvents, rows.Err()
 }
 
-func (s *currentRoomStateStatements) SelectKnownUsers(ctx context.Context, searchString string, limit int) ([]string, error) {
-	rows, err := s.selectKnownUsersStmt.QueryContext(ctx, fmt.Sprintf("%%%s%%", searchString), limit)
+func (s *currentRoomStateStatements) SelectKnownUsers(ctx context.Context, userID, searchString string, limit int) ([]string, error) {
+	rows, err := s.selectKnownUsersStmt.QueryContext(ctx, userID, fmt.Sprintf("%%%s%%", searchString), limit)
 	if err == sql.ErrNoRows {
 		return nil, nil
 	}
diff --git a/currentstateserver/storage/shared/storage.go b/currentstateserver/storage/shared/storage.go
index 40cc94549..bd4329a7d 100644
--- a/currentstateserver/storage/shared/storage.go
+++ b/currentstateserver/storage/shared/storage.go
@@ -90,6 +90,6 @@ func (d *Database) JoinedUsersSetInRooms(ctx context.Context, roomIDs []string)
 	return d.CurrentRoomState.SelectJoinedUsersSetForRooms(ctx, roomIDs)
 }
 
-func (d *Database) GetKnownUsers(ctx context.Context, searchString string, limit int) ([]string, error) {
-	return d.CurrentRoomState.SelectKnownUsers(ctx, searchString, limit)
+func (d *Database) GetKnownUsers(ctx context.Context, userID, searchString string, limit int) ([]string, error) {
+	return d.CurrentRoomState.SelectKnownUsers(ctx, userID, searchString, limit)
 }
diff --git a/currentstateserver/storage/sqlite3/current_room_state_table.go b/currentstateserver/storage/sqlite3/current_room_state_table.go
index d3bc86dde..418b4079b 100644
--- a/currentstateserver/storage/sqlite3/current_room_state_table.go
+++ b/currentstateserver/storage/sqlite3/current_room_state_table.go
@@ -71,7 +71,9 @@ const selectJoinedUsersSetForRoomsSQL = "" +
 	"SELECT state_key, COUNT(room_id) FROM currentstate_current_room_state WHERE room_id IN ($1) AND type = 'm.room.member' and content_value = 'join' GROUP BY state_key"
 
 const selectKnownUsersSQL = "" +
-	"SELECT DISTINCT state_key FROM currentstate_current_room_state WHERE type = 'm.room.member' AND state_key LIKE $1 LIMIT $2"
+	"SELECT DISTINCT state_key FROM currentstate_current_room_state WHERE room_id IN (" +
+	"  SELECT DISTINCT room_id FROM currentstate_current_room_state WHERE state_key=$1 AND TYPE='m.room.member' AND content_value='join'" +
+	") AND TYPE='m.room.member' AND content_value='join' AND state_key LIKE $2 LIMIT $3"
 
 type currentRoomStateStatements struct {
 	db                               *sql.DB
@@ -324,8 +326,8 @@ func (s *currentRoomStateStatements) SelectBulkStateContent(
 	return strippedEvents, rows.Err()
 }
 
-func (s *currentRoomStateStatements) SelectKnownUsers(ctx context.Context, searchString string, limit int) ([]string, error) {
-	rows, err := s.selectKnownUsersStmt.QueryContext(ctx, fmt.Sprintf("%%%s%%", searchString), limit)
+func (s *currentRoomStateStatements) SelectKnownUsers(ctx context.Context, userID, searchString string, limit int) ([]string, error) {
+	rows, err := s.selectKnownUsersStmt.QueryContext(ctx, userID, fmt.Sprintf("%%%s%%", searchString), limit)
 	if err == sql.ErrNoRows {
 		return nil, nil
 	}
diff --git a/currentstateserver/storage/tables/interface.go b/currentstateserver/storage/tables/interface.go
index 817ee3885..6290e7b3d 100644
--- a/currentstateserver/storage/tables/interface.go
+++ b/currentstateserver/storage/tables/interface.go
@@ -39,8 +39,8 @@ type CurrentRoomState interface {
 	// SelectJoinedUsersSetForRooms returns the set of all users in the rooms who are joined to any of these rooms, along with the
 	// counts of how many rooms they are joined.
 	SelectJoinedUsersSetForRooms(ctx context.Context, roomIDs []string) (map[string]int, error)
-	// SelectKnownUsers searches all users that we know about.
-	SelectKnownUsers(ctx context.Context, searchString string, limit int) ([]string, error)
+	// SelectKnownUsers searches all users that userID knows about.
+	SelectKnownUsers(ctx context.Context, userID, searchString string, limit int) ([]string, error)
 }
 
 // StrippedEvent represents a stripped event for returning extracted content values.