Gainer may refer to:
Sports moves Gainer (sports), a backward somersault in acrobatics, diving and some martial arts Gainer flash, a gainer combined with a flashkick
Other uses Gainer, a term related to fat fetishism Gainer (surname), includes a list of people with the name Gainer (supplement), a bodybuilding dietary product Gainer (racing team), a Japanese racing team Gainer the Gopher, mascot of the Saskatchewan Roughriders Overman King Gainer, a Japanese anime