Most Popular Extensions

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Adblock Plus No Restart Featured

Blocks annoying video ads on YouTube, Facebook ads, banners and much more.

Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).

Rated 5 out of 5 stars (4,299)
18,672,986 users

Video DownloadHelper

The easy way to download and convert Web videos from hundreds of YouTube-like sites.
This works also for audio and picture galleries.

Rated 4 out of 5 stars (4,219)
5,926,179 users

Firebug No Restart

Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page...

Rated 5 out of 5 stars (1,650)
2,685,104 users

NoScript Security Suite Featured

The best security you can get in a web browser!
Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.

Rated 5 out of 5 stars (1,320)
2,193,669 users

Microsoft .NET Framework Assistant

Adds ClickOnce support and the ability to report installed .NET versions to the web server.

Rated 2 out of 5 stars (116)
1,818,236 users

Greasemonkey Featured

Customize the way a web page displays or behaves, by using small bits of JavaScript.

Rated 4 out of 5 stars (866)
1,621,873 users

DownThemAll! Featured

The first and only download manager/accelerator built inside Firefox!

Rated 5 out of 5 stars (1,403)
1,553,790 users

Flash Video Downloader - YouTube Full HD Download

Flash Video Downloader helps you to download any video (flv, mp4, HD) from YouTube-like, Facebook, Break, Metacafe and more in one click. You can download mp3, music (iPod), avi and more. Download Flash games. Download Helper.

Rated 4 out of 5 stars (464)
1,267,541 users

Web of Trust - WOT Featured

Find out which websites you can trust. WOT adds intuitive traffic light-style icons next to search results and URLs to help you make informed decisions about whether to visit a site or not.

Rated 4 out of 5 stars (1,338)
1,256,781 users

FlashGot Mass Downloader Featured

Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.

Rated 5 out of 5 stars (430)
1,207,790 users

Adblock Plus Pop-up Addon

Adblock Plus Pop-up Addon extends the blocking functionality of Adblock Plus to those annoying pop-up windows that open on mouse clicks and other user actions.

Rated 4 out of 5 stars (161)
1,190,181 users

Ghostery No Restart Featured

Protect your privacy. See who's tracking your web browsing and block them with Ghostery.

Rated 5 out of 5 stars (860)
1,169,799 users

Tab Mix Plus Featured

Tab Mix Plus enhances Firefox's tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more. It also includes a full-featured session manager.

Rated 4 out of 5 stars (2,177)
1,089,837 users

Download Statusbar

View and manage downloads from a tidy statusbar - without the download window getting in the way of your web browsing.

Thanks Tekzilla for your awesome review! Click here to see their video: http://youtu.be/BUDqWrJ-Vao

Rated 4 out of 5 stars (1,372)
965,245 users

Flashblock

Never be annoyed by a Flash animation again! Blocks Flash so it won't get in your way, but if you want to see it, just click on...

Rated 4 out of 5 stars (885)
940,240 users

Element Hiding Helper for Adblock Plus No Restart

Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.

Rated 5 out of 5 stars (372)
903,632 users

Download YouTube Videos as MP4 No Restart Featured

An extension that adds direct links to download YouTube videos as MP4 and FLV. It has a simple interface and it downloads videos directly from YouTube. The extension integrates with YouTube's interface and adds a download button below the player.

Rated 4 out of 5 stars (238)
855,780 users

Flagfox No Restart Featured

Displays a country flag depicting the location of the current website's server and provides a multitude of tools such as site safety checks, whois, translation, similar sites, validation, URL shortening, and more...

Rated 5 out of 5 stars (581)
803,994 users

1-Click YouTube Video Download

The simplest YouTube Video Downloader for all YouTube Flash sites, period.

Rated 4 out of 5 stars (356)
774,853 users

Test Pilot

Help us make Firefox better by joining our structured user studies! No need to download this add-on if you are running Firefox 4 beta, - you are already a part of the team!

Rated 4 out of 5 stars (63)
717,861 users