How to Install Extensions (Add-ons) in Mozilla Firefox

Firefox logo on a purple background

An extension is an add-on to the browser that adds functionality. Extensions can be tools that extend the abilities of the Mozilla Firefox browser. Other types of extensions add integration with services, making them more convenient to use in the browser.

Firefox classifies extensions as a type of “Add-On” along with Themes. Unlike with some other browsers, such as Google Chrome, Firefox not only supports add-ons on your desktop, but also in the Android app.

Mozilla maintains a repository of all the add-ons. Not all of the extensions you can use on the desktop are available for Android. We’ll show you how to find and install them on both platforms.

Install Extensions in Firefox for Desktop

Open Firefox on your Windows 10, Mac, or Linux PC. From there, click the hamburger menu icon in the top-right corner of the window.

click the menu icon

Next, select “Add-Ons” from the drop-down menu.

select add-ons from menu

This is where any extensions or themes you have installed can be found. To download extensions, click “Find More Add-Ons” at the bottom of the page.

find more add-ons

You’re now on Mozilla’s storefront for add-ons. Click the “Extensions” tab to browse, or use the search box at the top of the screen.

extensions tab or search box

Once you find an extension that you like, select it to see more information about it. Click “Add to Firefox” to install the extension.

add to firefox button

A pop-up will appear with information about the permissions required for the extension. Click “Add” to continue the installation.

add the extension

Lastly, a message will show you where the extension lives. Click “Okay, Got It” to finish up.

okay got it to finish up

The Firefox add-on is now installed and running on your computer.

RELATED: Did You Know Browser Extensions Are Looking at Your Bank Account?

Install Extensions on Firefox for Android

Firefox for Android doesn’t have as many extensions as the desktop app, but it still has more than most mobile browsers.

First, open Firefox on your Android phone or tablet and tap the three-dot menu icon in the bottom bar.

open the menu icon

Next, select “Add-Ons” from the menu.

select add-ons

This is the list of available extensions for the Android app. Tap the extension name to see more information, then tap “+” to install the add-on.

tap the plus to install

A pop-up message will explain the required permissions. Tap “Add” to continue installing.

tap Add

Lastly, a message will show you where the extension can be accessed. Tap “Okay, Got It” to finish up.

okay got it to finish up


Firefox was one of the first browsers to support extensions, and it still boasts a great selection. It’s great that some of the extensions are available on Android, too. Now that you know how to install them, go forth and make the browser even better.

RELATED: How to Choose Which Extensions Appear on the Firefox Toolbar