fun. is an American alternative pop-rock band which formed in New York City in 2008. In February 2015, the band announced that they were not splitting up, but taking some time off to pursue other projects.

The band consists of Nate Ruess (vocals), Andrew Dost (keyboard, bass) and Jack Antonoff (guitar, trumpet). Ruess is a former member of The Format, Andrew Dost is a former member of Anathallo and Jack Antonoff is a member of Steel Train. The band also includes touring members Nate Harold (bass)