The announcement was made at its developer event being held in Orlando, Florida.
The OS is not dead, however, as Mozilla says it will continue to see how it can work on other connected devices.
Curiously, as this announcement was being made at the conference, the Mozilla Corporation's chief legal and business office Denelle Dixon-Thayer put out a long statement on the The Mozilla Blog, which made absolutely no mention of ending the smartphone project!
Little information has been provided by Mozilla about ceasing its smartphone experiment. This is in keeping with the trend of an open source organisation that has grown to be dominated by suits.
"Firefox OS proved the flexibility of the Web, scaling from low-end smartphones all the way up to HD TVs. However, we weren't able to offer the best user experience possible and so we will stop offering Firefox OS smartphones through carrier channels.
"We’ll share more on our work and new experiments across connected devices soon."
Phones with Firefox OS were first launched in July 2013, but failed to gain enough traction on in a market crowded with low-end Android devices.