Marion Anthony "Fat Tony" D'Amico (voiced by Joe Mantegna) is the fictional local Mafia Don and leader of the Springfield Mafia in the animated television series The Simpsons.

Fat Tony is a pastiche of Mafia characters from movies and dramas. His fellow mobsters include Joey, Legs, Louie, and occasionally Johnny Tightlips. Tony's schemes have ranged from supplying rat's milk to the school cafeteria to dabbling in the illegal fireworks racket. His gang also attempts to monopolize various legitimate business, once waging war with the local Yakuza over Marge Simpson's pretzel business.

In "Papa's Got a Brand New Badge", Tony put out a contract on Homer after his private security business interfered with the mob's interests. Homer would have been executed gangland-style if not for Maggie coming to the rescue with her rifle. Marge usually has a more peaceful relationship with Fat Tony, even driving his son Michael home from school. In the episode "Moe Baby Blues", she mentions that the mafia frequently congregates outside her house, and that she often brings them lemonade.

Fat Tony appears in "The Mook, the Chef, the Wife and Her Homer". His son Michael is introduced (he was mentioned earlier in "Moe Baby Blues" and "The Seven-Beer Snitch") and Bart reveals that Fat Tony muscled McDonald's and Burger King out of Springfield so Krusty Burger can have a monopoly. The episode also reveals that Fat Tony's wife (whom Marge admitted to not having met) was whacked by natural causes, and that he once nearly killed Chief Wiggum.

Fat Tony also keeps up on news and knew that Troy McClure had been sleeping with the fishes in A Fish Called Selma.

Though not strictly a "business" dealing, he has shown to be involved in gambling several times, most notably in the episode "Homie the Clown", in which he made numerous sports bets with Krusty.

Fat Tony is also a competent violinist, and his favorite movie is Divine Secrets of the Ya-Ya Sisterhood.