If you’ve ever felt like your browser just doesn’t do enough, fingers crossed this is the article you needed. Firefox has always been the browser for people who want more control, and extensions (also called add-ons) are the main reason why. Want to block ads, manage passwords, change how new tabs look, or give Firefox a whole new look? There’s an extension for all of that.
The good news is that installing and managing Firefox extensions is genuinely easy once you know where to look. In this guide, you’ll learn how to find extensions, install them safely, manage the ones you have, and even swap out Firefox’s appearance with themes, all using the current Firefox interface in 2026.
What Are Firefox Extensions (Add-ons)?
Firefox uses the word “add-ons” as an umbrella term, but in practice, most of what you’ll deal with falls into a handful of categories. Here’s a quick breakdown:
- Extensions – These add or change features in Firefox. Think ad blockers, password managers, tab organizers, and productivity tools. This is the big one.
- Themes – Change the color scheme and background of the Firefox interface itself. Purely cosmetic, but fun.
- Dictionaries / Language Packs – Add spell-checking support for different languages.
- Search Engines – Add extra search providers to Firefox’s address bar suggestions.
One thing worth knowing: old-style “plugins” (like Adobe Flash or Java) are no longer part of modern Firefox. That whole era is over, and honestly, good riddance. They were a security nightmare. Today’s extensions use a standard called WebExtensions, which is similar to how Chrome extensions work, making them safer and more stable.
Before You Begin
- A computer running Windows 10/11, macOS, or Linux with Firefox installed
- The latest version of Firefox (extensions work best on current Firefox, check Help > About Firefox to update)
- An internet connection
How to Find and Install Firefox Extensions
There are two ways to find extensions: directly inside Firefox, or by browsing the Mozilla Add-ons website (AMO). Both eventually take you to the same place, but the website gives you better browsing and filtering options if you’re just exploring.
Method 1: Through Firefox Itself
Step 1: Open Add-ons and Themes
Click the hamburger menu (the three horizontal lines in the top-right corner of Firefox), then click Add-ons and themes.
You can also skip the menu entirely by pressing Ctrl + Shift + A on Windows/Linux or Command + Shift + A on macOS. This opens the Add-ons Manager in a new tab.
Step 2: Search for an Extension
In the Add-ons Manager, click Extensions in the left sidebar if it isn’t already selected. Then use the Search all add-ons field at the top to type what you’re looking for, something like “ad blocker” or “dark mode.”
Press Enter and Firefox will open the search results on addons.mozilla.org in a new tab.
Step 3: Pick an Extension and Install It
Click on any extension in the results to open its detail page. Look for the Add to Firefox button and click it.
Firefox will show you a permissions prompt, which tells you exactly what the extension is allowed to do, like “access data on websites you visit.” Take a quick look at this before clicking Add. If an extension is asking for way more access than it needs to do its job, that’s a red flag.
After installation, Firefox may ask whether you want the extension to run in Private Windows. Choose Allow if you want it active during private browsing, or Don’t allow to keep it out of private sessions. Either way, the extension is now installed!
Method 2: Browse the Mozilla Add-ons Website
If you’d rather browse and explore, head straight to addons.mozilla.org. The website lets you filter by category, sort by most popular or top rated, and browse Mozilla’s Recommended Extensions, a curated list of well-maintained, security-reviewed extensions that Mozilla has personally vetted. This is the safest starting point if you’re not sure what to look for.
When you find something you want, click Add to Firefox right from the website, it’ll trigger the same installation prompt inside your browser.
How to Manage Your Installed Extensions
Finding Your Extensions After Install
After installing an extension, its icon might appear in the Firefox toolbar to the right of the address bar. If you don’t see it, don’t panic. It’s probably hiding in the Extensions menu (the puzzle-piece icon on the toolbar). Click the puzzle piece to see all your installed extensions, and click the pin icon next to any extension to add it to your toolbar permanently.
Disabling or Removing an Extension
Open the Add-ons Manager (Ctrl + Shift + A / Command + Shift + A), then click Extensions in the sidebar. You’ll see all your installed extensions listed here.
- To disable an extension: Use the toggle switch next to its name. The extension stays installed but goes dormant, which is handy if you want to take a break from it without losing your settings.
- To remove an extension completely: Click the three-dot menu (…) on the extension’s card and choose Remove. Confirm, and it’s gone.
You can also right-click any extension’s toolbar icon for quick options like Remove Extension… or Manage Extension without having to dig into the Add-ons Manager at all.
Configuring Extension Settings
Many extensions have their own settings you can tweak. In the Add-ons Manager, click the three-dot menu (…) on an extension and look for Options or Preferences. This opens the extension’s settings page where you can customize how it behaves.
How to Install and Change Firefox Themes
Themes change the look of the Firefox interface itself, including colors, backgrounds, and the whole vibe. They don’t affect how websites look, just the browser shell around them.
Step 1: Open the Themes Section
Open the Add-ons Manager and click Themes in the left sidebar.
Step 2: Switch to a Theme You’ve Already Installed
If you have multiple themes installed, just click Enable next to the one you want to activate. No restart needed. Firefox switches instantly.
Step 3: Find New Themes
Click Find more themes at the bottom of the Themes page. This takes you to the themes section of addons.mozilla.org, where you can browse thousands of options. Click any theme you like, then click Install Theme to apply it.
To go back to the default look, open Themes in the Add-ons Manager and click Enable next to System theme or Default.
Managing Search Engines
You can also add extra search engines to Firefox’s address bar, which is useful if you frequently search on sites like DuckDuckGo, Bing, or a specialized search tool.
- Click the hamburger menu and select Settings.
- In the left sidebar, click Search.
- Under Default Search Engine, pick your preferred search engine from the dropdown.
- Under Search Shortcuts, check or uncheck engines to control which ones appear in address bar suggestions.
Need a search engine that isn’t listed? You can find additional search engine add-ons on addons.mozilla.org by searching for the site’s name.
Tips and Troubleshooting
Common Issues
Problem: I installed an extension but can’t see its icon anywhere.
The extension is probably installed and working. It’s just hidden. Click the puzzle-piece Extensions icon on the toolbar to find it. Once you see it there, click the pin icon to move it to your main toolbar.
Problem: Firefox says it can’t install the extension or that it’s “not verified.”
Modern Firefox only installs signed extensions, meaning ones that Mozilla has reviewed and approved. If you’re seeing this error, make sure you’re installing from addons.mozilla.org and that your Firefox is up to date. Avoid downloading random .xpi files from other websites. That’s how things go wrong.
Problem: An extension I’ve used for years stopped working after a Firefox update.
This happens occasionally. The first thing to try is updating the extension itself. Open the Add-ons Manager, click the gear icon, and select Check for Updates. If there’s no update available, check the extension’s page on AMO for any notes about compatibility issues. If it’s completely broken, search AMO for a modern replacement.
Problem: I’m looking for a Chrome extension but can’t find it for Firefox.
Firefox and Chrome both use a similar WebExtensions format, but they’re not identical, so some Chrome extensions don’t have Firefox versions. Search AMO for the same functionality by keyword (e.g., “tab manager” or “grammar checker”) and you’ll usually find a Firefox equivalent.
Pro Tips
- Start with Recommended Extensions: Mozilla’s Recommended Extensions program highlights add-ons that have been manually reviewed for quality and security. It’s the safest way to explore without worrying about installing something sketchy.
- Don’t go overboard: Every extension you install uses a little memory and can slow down Firefox. Keep only what you actually use. If you’re noticing Firefox getting sluggish, open
about:performancein the address bar to see which extensions are hogging resources.
- Check permissions before installing: A flashlight app asking for your contacts is a red flag on your phone, and the same logic applies here. If an extension’s permissions seem way too broad for what it claims to do, skip it.
- Extensions on Firefox for Android: Many popular extensions now work on Firefox for Android too, though the catalog is smaller than desktop. Check the extension’s AMO page to see if it supports mobile.
- Built-in features you might not need extensions for: Modern Firefox already has a built-in screenshot tool, PDF editor, reader view, and strong tracking protection. Before installing an extension for one of these things, check if Firefox already does it natively.
Wrapping Up
Firefox extensions are genuinely one of the best things about the browser, and now you know exactly how to find them, install them safely, and keep them under control. Start with Mozilla’s Recommended Extensions if you’re not sure where to begin, and remember that less is more when it comes to how many you run at once.
If you want to get even more out of Firefox, check out our guide on making Firefox faster and our article on useful about:config tweaks. A well-tuned Firefox with the right extensions is honestly hard to beat.