diff --git a/package.json b/package.json
index 61b2a27acc..ad7de2941c 100644
--- a/package.json
+++ b/package.json
@@ -104,6 +104,7 @@
     "tar-js": "^0.3.0",
     "text-encoding-utf-8": "^1.0.2",
     "url": "^0.11.0",
+    "web-streams-polyfill": "^3.0.3",
     "what-input": "^5.2.10",
     "zxcvbn": "^4.4.2"
   },
diff --git a/src/utils/exportUtils/HtmlExport.ts b/src/utils/exportUtils/HtmlExport.ts
index 894e8571ef..755792079a 100644
--- a/src/utils/exportUtils/HtmlExport.ts
+++ b/src/utils/exportUtils/HtmlExport.ts
@@ -7,6 +7,7 @@ import { Room } from "matrix-js-sdk/src/models/room";
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 import { getUserNameColorClass } from "../FormattingUtils";
 import { Exporter } from "./Exporter";
+import * as ponyfill from 'web-streams-polyfill/ponyfill'
 
 const css = `
 body {
@@ -485,6 +486,8 @@ export default class HTMLExporter extends Exporter {
         //Generate the zip file asynchronously
         const blob = await this.zip.generateAsync({ type: "blob" });
 
+        //Support for firefox browser
+        streamSaver.WritableStream = ponyfill.WritableStream
         //Create a writable stream to the directory
         const fileStream = streamSaver.createWriteStream(filename, { size: blob.size });
         const writer = fileStream.getWriter();
diff --git a/yarn.lock b/yarn.lock
index 982b9e607b..d2c1a8f71d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -8337,6 +8337,11 @@ walker@^1.0.7, walker@~1.0.5:
   dependencies:
     makeerror "1.0.x"
 
+web-streams-polyfill@^3.0.3:
+  version "3.0.3"
+  resolved "https://registry.yarnpkg.com/web-streams-polyfill/-/web-streams-polyfill-3.0.3.tgz#f49e487eedeca47a207c1aee41ee5578f884b42f"
+  integrity sha512-d2H/t0eqRNM4w2WvmTdoeIvzAUSpK7JmATB8Nr2lb7nQ9BTIJVjbQ/TRFVEh2gUH1HwclPdoPtfMoFfetXaZnA==
+
 webcrypto-core@^1.1.8:
   version "1.1.8"
   resolved "https://registry.yarnpkg.com/webcrypto-core/-/webcrypto-core-1.1.8.tgz#91720c07f4f2edd181111b436647ea5a282af0a9"