Mario & Luigi: Superstar Saga, known in Japan as Mario & Luigi RPG (マリオ＆ルイージRPG Mario ando Ruīji Aru Pī Jī?), is a role-playing video game developed by AlphaDream and published by Nintendo for the Game Boy Advance in 2003. The first game in the Mario & Luigi RPG series, Superstar Saga was followed by three sequels: Mario & Luigi: Partners in Time and Mario & Luigi: Bowser's Inside Story for the Nintendo DS, and Mario & Luigi: Dream Team for the Nintendo 3DS. The game was later re-released for the Wii U Virtual Console on the Nintendo eShop in 2014.

The setting of the game begins in the Mushroom Kingdom, but progresses to the Beanbean Kingdom for the majority of the game. In the game, Mario and Luigi combat Cackletta, the primary antagonist. The quest begins when Cackletta, with the aid of her assistant Fawful, steals Princess Peach's voice after adopting the guise of an ambassador from Beanbean Kingdom.

A role-playing game, it centers on a battle system different from that of traditional games of the genre, with emphasis on timing and more elaborate attacks. The game is whimsical in tone, with various in-game jokes and comical references to the heritage of the Mario series. Superstar Saga was generally well received by critics, and IGN named it the twelfth best Game Boy Advance game of all time in their feature reflecting on the Game Boy Advance's lifespan. less