diff --git a/clientapi/routing/routing.go b/clientapi/routing/routing.go
index 0c63f968..14acc42f 100644
--- a/clientapi/routing/routing.go
+++ b/clientapi/routing/routing.go
@@ -639,7 +639,7 @@ func Setup(
 				req.Context(),
 				device,
 				userAPI,
-				stateAPI,
+				rsAPI,
 				cfg.Matrix.ServerName,
 				postContent.SearchString,
 				postContent.Limit,
diff --git a/clientapi/routing/userdirectory.go b/clientapi/routing/userdirectory.go
index db81ffea..2659bc9c 100644
--- a/clientapi/routing/userdirectory.go
+++ b/clientapi/routing/userdirectory.go
@@ -19,7 +19,7 @@ import (
 	"fmt"
 
 	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
-	currentstateAPI "github.com/matrix-org/dendrite/currentstateserver/api"
+	"github.com/matrix-org/dendrite/roomserver/api"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
@@ -34,7 +34,7 @@ func SearchUserDirectory(
 	ctx context.Context,
 	device *userapi.Device,
 	userAPI userapi.UserInternalAPI,
-	stateAPI currentstateAPI.CurrentStateInternalAPI,
+	rsAPI api.RoomserverInternalAPI,
 	serverName gomatrixserverlib.ServerName,
 	searchString string,
 	limit int,
@@ -81,14 +81,14 @@ func SearchUserDirectory(
 	// start searching for known users from joined rooms.
 
 	if len(results) <= limit {
-		stateReq := &currentstateAPI.QueryKnownUsersRequest{
+		stateReq := &api.QueryKnownUsersRequest{
 			UserID:       device.UserID,
 			SearchString: searchString,
 			Limit:        limit - len(results),
 		}
-		stateRes := &currentstateAPI.QueryKnownUsersResponse{}
-		if err := stateAPI.QueryKnownUsers(ctx, stateReq, stateRes); err != nil {
-			errRes := util.ErrorResponse(fmt.Errorf("stateAPI.QueryKnownUsers: %w", err))
+		stateRes := &api.QueryKnownUsersResponse{}
+		if err := rsAPI.QueryKnownUsers(ctx, stateReq, stateRes); err != nil {
+			errRes := util.ErrorResponse(fmt.Errorf("rsAPI.QueryKnownUsers: %w", err))
 			return &errRes
 		}
 
diff --git a/currentstateserver/api/api.go b/currentstateserver/api/api.go
index 4ebe2968..b778acb2 100644
--- a/currentstateserver/api/api.go
+++ b/currentstateserver/api/api.go
@@ -20,7 +20,6 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
@@ -34,8 +33,6 @@ type CurrentStateInternalAPI interface {
 	QueryBulkStateContent(ctx context.Context, req *QueryBulkStateContentRequest, res *QueryBulkStateContentResponse) error
 	// QuerySharedUsers returns a list of users who share at least 1 room in common with the given user.
 	QuerySharedUsers(ctx context.Context, req *QuerySharedUsersRequest, res *QuerySharedUsersResponse) error
-	// QueryKnownUsers returns a list of users that we know about from our joined rooms.
-	QueryKnownUsers(ctx context.Context, req *QueryKnownUsersRequest, res *QueryKnownUsersResponse) error
 }
 
 type QuerySharedUsersRequest struct {
@@ -91,16 +88,6 @@ type QueryCurrentStateResponse struct {
 	StateEvents map[gomatrixserverlib.StateKeyTuple]*gomatrixserverlib.HeaderedEvent
 }
 
-type QueryKnownUsersRequest struct {
-	UserID       string `json:"user_id"`
-	SearchString string `json:"search_string"`
-	Limit        int    `json:"limit"`
-}
-
-type QueryKnownUsersResponse struct {
-	Users []authtypes.FullyQualifiedProfile `json:"profiles"`
-}
-
 // MarshalJSON stringifies the StateKeyTuple keys so they can be sent over the wire in HTTP API mode.
 func (r *QueryCurrentStateResponse) MarshalJSON() ([]byte, error) {
 	se := make(map[string]*gomatrixserverlib.HeaderedEvent, len(r.StateEvents))
diff --git a/currentstateserver/internal/api.go b/currentstateserver/internal/api.go
index dc255412..c581c524 100644
--- a/currentstateserver/internal/api.go
+++ b/currentstateserver/internal/api.go
@@ -17,7 +17,6 @@ package internal
 import (
 	"context"
 
-	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
 	"github.com/matrix-org/dendrite/currentstateserver/api"
 	"github.com/matrix-org/dendrite/currentstateserver/storage"
 	"github.com/matrix-org/gomatrixserverlib"
@@ -50,19 +49,6 @@ func (a *CurrentStateInternalAPI) QueryRoomsForUser(ctx context.Context, req *ap
 	return nil
 }
 
-func (a *CurrentStateInternalAPI) QueryKnownUsers(ctx context.Context, req *api.QueryKnownUsersRequest, res *api.QueryKnownUsersResponse) error {
-	users, err := a.DB.GetKnownUsers(ctx, req.UserID, req.SearchString, req.Limit)
-	if err != nil {
-		return err
-	}
-	for _, user := range users {
-		res.Users = append(res.Users, authtypes.FullyQualifiedProfile{
-			UserID: user,
-		})
-	}
-	return nil
-}
-
 func (a *CurrentStateInternalAPI) QueryBulkStateContent(ctx context.Context, req *api.QueryBulkStateContentRequest, res *api.QueryBulkStateContentResponse) error {
 	events, err := a.DB.GetBulkStateContent(ctx, req.RoomIDs, req.StateTuples, req.AllowWildcards)
 	if err != nil {
diff --git a/currentstateserver/inthttp/client.go b/currentstateserver/inthttp/client.go
index 37d289ea..18151f63 100644
--- a/currentstateserver/inthttp/client.go
+++ b/currentstateserver/inthttp/client.go
@@ -98,13 +98,3 @@ func (h *httpCurrentStateInternalAPI) QuerySharedUsers(
 	apiURL := h.apiURL + QuerySharedUsersPath
 	return httputil.PostJSON(ctx, span, h.httpClient, apiURL, req, res)
 }
-
-func (h *httpCurrentStateInternalAPI) QueryKnownUsers(
-	ctx context.Context, req *api.QueryKnownUsersRequest, res *api.QueryKnownUsersResponse,
-) error {
-	span, ctx := opentracing.StartSpanFromContext(ctx, "QueryKnownUsers")
-	defer span.Finish()
-
-	apiURL := h.apiURL + QueryKnownUsersPath
-	return httputil.PostJSON(ctx, span, h.httpClient, apiURL, req, res)
-}
diff --git a/currentstateserver/inthttp/server.go b/currentstateserver/inthttp/server.go
index aee900e0..f4e93dcd 100644
--- a/currentstateserver/inthttp/server.go
+++ b/currentstateserver/inthttp/server.go
@@ -77,17 +77,4 @@ func AddRoutes(internalAPIMux *mux.Router, intAPI api.CurrentStateInternalAPI) {
 			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
 		}),
 	)
-	internalAPIMux.Handle(QuerySharedUsersPath,
-		httputil.MakeInternalAPI("queryKnownUsers", func(req *http.Request) util.JSONResponse {
-			request := api.QueryKnownUsersRequest{}
-			response := api.QueryKnownUsersResponse{}
-			if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
-				return util.MessageResponse(http.StatusBadRequest, err.Error())
-			}
-			if err := intAPI.QueryKnownUsers(req.Context(), &request, &response); err != nil {
-				return util.ErrorResponse(err)
-			}
-			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
-		}),
-	)
 }
diff --git a/roomserver/inthttp/server.go b/roomserver/inthttp/server.go
index ebfb296d..97f2a360 100644
--- a/roomserver/inthttp/server.go
+++ b/roomserver/inthttp/server.go
@@ -364,7 +364,7 @@ func AddRoutes(r api.RoomserverInternalAPI, internalAPIMux *mux.Router) {
 			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
 		}),
 	)
-	internalAPIMux.Handle(RoomserverQuerySharedUsersPath,
+	internalAPIMux.Handle(RoomserverQueryKnownUsersPath,
 		httputil.MakeInternalAPI("queryKnownUsers", func(req *http.Request) util.JSONResponse {
 			request := api.QueryKnownUsersRequest{}
 			response := api.QueryKnownUsersResponse{}
diff --git a/syncapi/internal/keychange_test.go b/syncapi/internal/keychange_test.go
index 6765fa65..92573baa 100644
--- a/syncapi/internal/keychange_test.go
+++ b/syncapi/internal/keychange_test.go
@@ -57,10 +57,6 @@ func (s *mockCurrentStateAPI) QueryCurrentState(ctx context.Context, req *api.Qu
 	return nil
 }
 
-func (s *mockCurrentStateAPI) QueryKnownUsers(ctx context.Context, req *api.QueryKnownUsersRequest, res *api.QueryKnownUsersResponse) error {
-	return nil
-}
-
 // QueryRoomsForUser retrieves a list of room IDs matching the given query.
 func (s *mockCurrentStateAPI) QueryRoomsForUser(ctx context.Context, req *api.QueryRoomsForUserRequest, res *api.QueryRoomsForUserResponse) error {
 	return nil