diff --git a/src/@types/requests.ts b/src/@types/requests.ts
index b985bec29..91ac85262 100644
--- a/src/@types/requests.ts
+++ b/src/@types/requests.ts
@@ -34,6 +34,7 @@ export interface IJoinRoomOpts {
 
     /**
      * The server names to try and join through in addition to those that are automatically chosen.
+     * Only the first 3 are actually used in the request, to avoid HTTP 414 Request-URI Too Long responses.
      */
     viaServers?: string[];
 
@@ -71,6 +72,7 @@ export interface KnockRoomOpts {
 
     /**
      * The server names to try and knock through in addition to those that are automatically chosen.
+     * Only the first 3 are actually used in the request, to avoid HTTP 414 Request-URI Too Long responses.
      */
     viaServers?: string | string[];
 }
diff --git a/src/client.ts b/src/client.ts
index 52029ce47..654f42353 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -2391,8 +2391,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
         const queryParams: QueryDict = {};
         if (opts.viaServers) {
             // server_name has been deprecated in favour of via with Matrix >1.11 (MSC4156)
-            queryParams.server_name = opts.viaServers;
-            queryParams.via = opts.viaServers;
+            // We only use the first 3 servers, to avoid URI length issues.
+            queryParams.via = queryParams.server_name = opts.viaServers.slice(0, 3);
         }
 
         const data: IJoinRequestBody = {};
@@ -2436,9 +2436,11 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
 
         const queryParams: QueryDict = {};
         if (opts.viaServers) {
+            // We only use the first 3 servers, to avoid URI length issues.
+            const viaServers = Array.isArray(opts.viaServers) ? opts.viaServers.slice(0, 3) : [opts.viaServers];
             // server_name has been deprecated in favour of via with Matrix >1.11 (MSC4156)
-            queryParams.server_name = opts.viaServers;
-            queryParams.via = opts.viaServers;
+            queryParams.server_name = viaServers;
+            queryParams.via = viaServers;
         }
 
         const body: Record<string, string> = {};