diff --git a/src/http-api/index.ts b/src/http-api/index.ts
index 346a9e54991..a556ced9413 100644
--- a/src/http-api/index.ts
+++ b/src/http-api/index.ts
@@ -73,8 +73,9 @@ export class MatrixHttpApi<O extends IHttpOpts> extends FetchHttpApi<O> {
                 uploadResolvers.reject(new Error("Timeout"));
             };
 
-            // set an initial timeout of 30s; we'll advance it each time we get a progress notification
-            let timeoutTimer = callbacks.setTimeout(timeoutFn, 30000);
+            // set an initial timeout (default to 30s); extendable via opts.timeoutMs
+            const timeoutDuration = opts.timeoutMs ?? 30000;
+            let timeoutTimer = callbacks.setTimeout(timeoutFn, timeoutDuration);
 
             xhr.onreadystatechange = function (): void {
                 switch (xhr.readyState) {
@@ -108,7 +109,7 @@ export class MatrixHttpApi<O extends IHttpOpts> extends FetchHttpApi<O> {
                 callbacks.clearTimeout(timeoutTimer);
                 upload.loaded = ev.loaded;
                 upload.total = ev.total;
-                timeoutTimer = callbacks.setTimeout(timeoutFn, 30000);
+                timeoutTimer = callbacks.setTimeout(timeoutFn, timeoutDuration);
                 opts.progressHandler?.({
                     loaded: ev.loaded,
                     total: ev.total,
diff --git a/src/http-api/interface.ts b/src/http-api/interface.ts
index 40100a5b552..70bac40c8f3 100644
--- a/src/http-api/interface.ts
+++ b/src/http-api/interface.ts
@@ -207,6 +207,11 @@ export interface UploadOpts {
      */
     progressHandler?(progress: UploadProgress): void;
     abortController?: AbortController;
+    /**
+     * Optional. Timeout in milliseconds before the upload is aborted.
+     *    Defaults to 30000 (30 seconds) if not specified.
+     */
+    timeoutMs?: number;
 }
 
 export interface Upload {