Mozilla says it's up to three times faster than the pre-loaded browser.
New features include the ability to hide browser controls when not in use, and to release more of the screen size to view websites.
Meanwhile Firefox Sync gives users access to their browsing history, bookmarks, open tabs, form data and passwords across computers and mobile devices.
Other changes include a "save to pdf" option which can save a webpage for offline viewing later.
Firefox is available from the Android Market and for download on Maemo devices in over 10 languages.