diff --git a/setup/mscs/msc2836/msc2836.go b/setup/mscs/msc2836/msc2836.go
index 15811710d..00b536183 100644
--- a/setup/mscs/msc2836/msc2836.go
+++ b/setup/mscs/msc2836/msc2836.go
@@ -23,10 +23,12 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"slices"
 	"sort"
 	"strings"
 	"time"
 
+	"github.com/gorilla/mux"
 	fs "github.com/matrix-org/dendrite/federationapi/api"
 	"github.com/matrix-org/dendrite/internal/hooks"
 	"github.com/matrix-org/dendrite/internal/httputil"
@@ -146,6 +148,43 @@ func Enable(
 			return federatedEventRelationship(req.Context(), fedReq, db, rsAPI, fsAPI)
 		},
 	)).Methods(http.MethodPost, http.MethodOptions)
+
+	if slices.Contains(cfg.MSCs.MSCs, "MSC3856") {
+		routers.Client.Handle("/unstable/org.matrix.msc3856/rooms/{roomID}/threads", httputil.MakeAuthAPI(
+			"msc3856_thread_list", userAPI, func(req *http.Request, d *userapi.Device) util.JSONResponse {
+				vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
+				if err != nil {
+					return util.ErrorResponse(err)
+				}
+
+				roomID := vars["roomID"]
+
+				childrens, err := db.GetChildrensByRoomId(req.Context(), roomID, true)
+				if err != nil {
+					return util.ErrorResponse(err)
+				}
+
+				chunks := make([]map[string]any, 0)
+				for _, child := range childrens {
+					chunks = append(chunks,
+						map[string]any{
+							"event_id":         child.EventID,
+							"origin_server_ts": child.OriginServerTS,
+							"room_id":          child.RoomID,
+						},
+					)
+				}
+
+				return util.JSONResponse{
+					Code: 200,
+					JSON: map[string]any{
+						"chunk":      chunks,
+						"next_batch": "next_batch_token",
+					},
+				}
+			},
+		))
+	}
 	return nil
 }
 
diff --git a/setup/mscs/msc2836/storage.go b/setup/mscs/msc2836/storage.go
index 696d0b0da..8f971e90a 100644
--- a/setup/mscs/msc2836/storage.go
+++ b/setup/mscs/msc2836/storage.go
@@ -43,19 +43,23 @@ type Database interface {
 	ChildMetadata(ctx context.Context, eventID string) (count int, hash []byte, explored bool, err error)
 	// MarkChildrenExplored sets the 'explored' flag on this event to `true`.
 	MarkChildrenExplored(ctx context.Context, eventID string) error
+
+	GetChildrensByRoomId(ctx context.Context, roomID string, recentFirst bool) ([]eventInfo, error)
 }
 
 type DB struct {
-	db                                     *sql.DB
-	writer                                 sqlutil.Writer
-	insertEdgeStmt                         *sql.Stmt
-	insertNodeStmt                         *sql.Stmt
-	selectChildrenForParentOldestFirstStmt *sql.Stmt
-	selectChildrenForParentRecentFirstStmt *sql.Stmt
-	selectParentForChildStmt               *sql.Stmt
-	updateChildMetadataStmt                *sql.Stmt
-	selectChildMetadataStmt                *sql.Stmt
-	updateChildMetadataExploredStmt        *sql.Stmt
+	db                                             *sql.DB
+	writer                                         sqlutil.Writer
+	insertEdgeStmt                                 *sql.Stmt
+	insertNodeStmt                                 *sql.Stmt
+	selectChildrenByRoomIdForParentOldestFirstStmt *sql.Stmt
+	selectChildrenByRoomIdForParentRecentFirstStmt *sql.Stmt
+	selectChildrenForParentOldestFirstStmt         *sql.Stmt
+	selectChildrenForParentRecentFirstStmt         *sql.Stmt
+	selectParentForChildStmt                       *sql.Stmt
+	updateChildMetadataStmt                        *sql.Stmt
+	selectChildMetadataStmt                        *sql.Stmt
+	updateChildMetadataExploredStmt                *sql.Stmt
 }
 
 // NewDatabase loads the database for msc2836
@@ -141,6 +145,18 @@ func newPostgresDatabase(conMan *sqlutil.Connections, dbOpts *config.DatabaseOpt
 	`); err != nil {
 		return nil, err
 	}
+	selectChildrenByRoomIdQuery := `
+	SELECT child_event_id, origin_server_ts, room_id FROM msc2836_edges
+		LEFT JOIN msc2836_nodes ON msc2836_edges.child_event_id = msc2836_nodes.event_id
+		WHERE room_id = $1
+		ORDER BY origin_server_ts`
+	if d.selectChildrenByRoomIdForParentOldestFirstStmt, err = d.db.Prepare(selectChildrenByRoomIdQuery + "ASC"); err != nil {
+		return nil, err
+	}
+	if d.selectChildrenByRoomIdForParentRecentFirstStmt, err = d.db.Prepare(selectChildrenByRoomIdQuery + "DESC"); err != nil {
+		return nil, err
+	}
+
 	return &d, err
 }
 
@@ -219,6 +235,17 @@ func newSQLiteDatabase(conMan *sqlutil.Connections, dbOpts *config.DatabaseOptio
 	`); err != nil {
 		return nil, err
 	}
+	selectChildrenByRoomIdQuery := `
+	SELECT child_event_id, origin_server_ts, room_id FROM msc2836_edges
+		LEFT JOIN msc2836_nodes ON msc2836_edges.child_event_id = msc2836_nodes.event_id
+		WHERE room_id = $1
+		ORDER BY origin_server_ts`
+	if d.selectChildrenByRoomIdForParentOldestFirstStmt, err = d.db.Prepare(selectChildrenByRoomIdQuery + "ASC"); err != nil {
+		return nil, err
+	}
+	if d.selectChildrenByRoomIdForParentRecentFirstStmt, err = d.db.Prepare(selectChildrenByRoomIdQuery + "DESC"); err != nil {
+		return nil, err
+	}
 	return &d, nil
 }
 
@@ -315,6 +342,30 @@ func (p *DB) ParentForChild(ctx context.Context, eventID, relType string) (*even
 	return &ei, nil
 }
 
+func (p *DB) GetChildrensByRoomId(ctx context.Context, roomID string, recentFirst bool) ([]eventInfo, error) {
+	var rows *sql.Rows
+	var err error
+	if recentFirst {
+		rows, err = p.selectChildrenForParentRecentFirstStmt.QueryContext(ctx, roomID)
+	} else {
+		rows, err = p.selectChildrenByRoomIdForParentOldestFirstStmt.QueryContext(ctx, roomID)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	defer rows.Close() // nolint: errcheck
+	var children []eventInfo
+	for rows.Next() {
+		var evInfo eventInfo
+		if err := rows.Scan(&evInfo.EventID, &evInfo.OriginServerTS, &evInfo.RoomID); err != nil {
+			return nil, err
+		}
+		children = append(children, evInfo)
+	}
+	return children, rows.Err()
+}
+
 func parentChildEventIDs(ev *types.HeaderedEvent) (parent, child, relType string) {
 	if ev == nil {
 		return