Flatiron is a mandolin and stringed-instrument brand founded in 1977 in Bozeman, Montana, by Charles "Chuck" Morrison. The name comes from the Flatirons, the slab-rock formations overlooking Boulder, Colorado, where Morrison had started building instruments before relocating to Montana. The shop initially produced flat-top mandolins and banjos, and in the mid-1980s added arched-top A-style and F-style mandolins that put it into direct competition with Gibson.

Gibson acquired Flatiron in 1987 and based its Montana acoustic operation in Bozeman, producing both Gibson and Flatiron instruments through the 1990s. Bozeman-era Flatirons — including models such as the Performer, Cadet, 1N, 2M, and the F-5 Artist — are valued by bluegrass and old-time players for their craftsmanship. Gibson moved Flatiron production to Nashville in 1996 and later shifted it overseas. Luthier Bruce Weber, who managed the Flatiron shop under Gibson, went on to found Weber Fine Acoustic Instruments in Montana after the Bozeman operation was consolidated.

Flatiron has 2 products cataloged on Equipboard, including Mandolins and Bouzoukis. Their gear is featured by 1 artist, with the strongest followings in Folk, World, & Country. Notable users include Chris Thile.