See also Featured Mozilla-based applications, many of which use XULRunner.

XULRunner 5+ based applications

These applications use XULRunner 5 or greater.

 
AZARDI
Free Win/Mac/Linux ePub 2/ePub 3 desktop reader using HTML5 and latest CSS features of Gecko for interactive e-books. Version updates match the rapid release cycle. Now available with XULRunner 30 with I18N support. MathML support is significant. Includes SMIL audio overlays and IDPF Fixed Layout.
celtx
All-in-one media pre-production software. Source
ChatZilla
A standalone version of the ChatZilla IRC client.
Conkeror
A highly programmable web browser with a leopard-oriented design inspired by Emacs. Source
Evergreen - Staff Client
Evergreen is an open source library system. Source
iEditWeb
A client/server based content manager and Internet Application suite. iEditWeb users can add pages, images, forms, ecommerce many special effects and much more using the Xulrunner based client. It will comunicate dyamically with the iEditWeb server to maintain a fully configured web site with embedded web applications. It also contains a built in email marketing system that is tightly integrated with the associated web site. One example of this tight integration is that the form in a web site can collect payment and set up a login for a members only section. A newsletter can be sent to members who sign up on a regular bases.
Instantbird
Multi-protocol IM client. Build instructions
Komodo Edit
A multi-language code development tool. Build instructions
Pencil
The Pencil Project's unique mission is to build a free and opensource tool for making diagrams and GUI prototyping that everyone can use. Source
Qiqqa
Research manager, reference manager, and PDF manager.  XULRunner is embedded to provide automatic search against journal archives, automatic acquisition of BibTeX information, and automatic downloading of PDFs.
SlimerJs

SlimerJS is a XulRunner application that can be launched with Firefox, allowing to execute an external javascript script which can manipulate web content.

Its goal is to provide a tool like PhantomJs, with the same API, except that it runs Gecko instead of Webkit, and it is not headless (but you can still use xvfb to have a headless SlimerJS).

SQLite Manager
Manage all your sqlite databases using this lightweight extension for firefox, thunderbird, seamonkey, songbird, komodo etc. SQLite Manager is also available as a XULRunner application.
Surebo Browselorer
A new, simple yet highly functional and customizable web browser, based on XULRunner 22.
Websecurify
Web Application Security Testing Environment. Source
Yoono Desktop
Win/Mac application to get all your friend updates, update your status and share stuff easily across Facebook, MySpace, Twitter, and more - all at once! Simplify your online social life.
Zotero
Reference manager with Firefox, Chrome, and Safari integration. Both Firefox extension and XULRunner-based standalone application available. Source

Applications based on XULRunner 1.9 or earlier

Buzzbird
XUL-based desktop twitter client. GitHub
BlueGriffon
The next-generation Web Editor based on the rendering engine of Firefox. Build instructions
Convertigo Enterprise Mashup Server
A Web integrator and Web clipper tool to build enterprise mashups
Nightingale
Nightingale is a communtiy fork of the Songbird media player, bringing back Linux support and much more. Build instructions
Kirix Strata
A new specialty browser for accessing and manipulating data from the web
TeleKast
An open source teleprompter and script editor. Source
TomTom HOME 2
PC application to manage TomTom GPS devices
Understanding Faith (Desktop Version)
A Multimedia Religious Education Resource for Catholic Secondary Schools in Australia.
ViViPOS
Integrated point-of-sales software-hardware solution with customized XUL Application as the device front-end. English site.

Inactive projects

These projects appear to be less actively developed, with no updates since 2010. They are all based on XULRunner 1.8 or earlier.

Abstract
An accounting package with breakthrough level of automation. Latest Release: 0.0.2  November 2010 - Source
Clines
A clone of Color Lines (game). Latest Release: 1.2 November 2008 - Source
CocoaPSYC.app
A PSYC IM/Chat client for Mac OS X (Also available as a Firefox extension). Latest Release 0.5 Febuary 2010 - Source
DAIM (fr) / DAIM (English)
superb tool for image analysis build on top of a professional imagelib.
Echofon for Windows
A Twitter client.
eMusic Remote
The eMusic Remote makes downloading from eMusic a snap. Latest release: 1.0.0.2 March 2009 - Source
FindThatFont!
Font managing tool for Windows and Linux, that helps you find the font you're looking for. Latest release December 2007
Flickr Uploadr 3.0
Upload your photos to Flickr. Source
Google AdWords Editor
AdWords Editor is Google's free, downloadable account management application for your computer. Latest release 7.6.1 January 2010 - XULRunner Patches
Lotus Notes / Sametime
The latest version of IBM Lotus Notes and Sametime can embed xul application.
Mockery
Mockery is a GUI design tool for creating and editing mockups, prototypes, and wireframes for web and desktop software. Latest release August 2010
Plain Old Webserver Google warns that this link is unsafe.
A fully-functioning webserver that runs server-side Javascript. Latest release June 2009
Prism (formerly known as Webrunner)
A simple, minimal web browser shell or "Single site browser." Useful for running web applications such as Gmail in a separate browser process.
Songbird
Songbird™ is a desktop Web player, a digital jukebox and Web browser mashup. Build instructions
Spicebird
A collaboration suite - e-mail, calendaring and instant messaging. Latest release: June 2010 - Build instructions

Utilities / Prototypes

AJAX Toolkit Framework (ATF)
A part of the Eclipse Web Tools Platform (WTP)
Aliwal Geocoder
Geocode addresses onto a map
Benjamin's XULRunner examples
"mybrowser is a very simple example browser", xulmine. An updated version of "mybrowser" that works with Firefox 25.0.1+ is available in Matthew Kastor's XULRunner examples at https://github.com/matthewkastor/XULRunner-Examples/
Exch
A currency conversion tool using updated data from http://finance.yahoo.com/currency. You can use the Firefox extension or the stand-alone XUL application.
OpenDocument Viewer
Cross-platform viewer for OpenDocument files.
TaskPool
TaskPool is a little application to help keep track of time. You can add tasks to a pool, turn them on and off, and it will tick off seconds.
SVGclock
An SVG-based clock.
Crowbar
A web scraping environment based on the use of a server-side headless mozilla-based browser.
30b
A XULRunner-based wrapper for 30boxes.com
XUL Explorer
"a lightweight XUL IDE... an easy way to experiment with XUL"
XULExplorer
A patched version of XUL Explorer to re-enable application and extension skeleton generation.
Foxkeh Clock (for Japanese page)
A clock application based charactor Foxkeh.
Pyjamas-Desktop
A Python Web Widget toolkit (similar to pyqt4 and pygtk2) that uses XULrunner DOM to implement the widgets and event handling. python-hulahop is required
Python-Hulahop from the OLPC Sugarlabs
A Python GTK Widget with XULrunner embedded, providing full access to nsI DOM and all other XULrunner interfaces, in a GTK window. It's possible to create your own python web browser with hulahop, and much much more besides.
XULJet
A framework that helps to create platform independent desktop applications directly in JavaScript