Mega Man III is an action-platform video game by Capcom for the Nintendo Game Boy. It is the third game in the handheld version of the Mega Man series. The game follows the title character Mega Man as he fights the evil Dr. Wily, whose latest attempt to conquer the world involves sucking energy from the Earth's core to power a new machine. Along with foes from his past, Mega Man must contend with the next robot in Wily's line of "Mega Man Killers", Punk. Like its two consecutive predecessors on the Game Boy, the game combines elements from two previously released Nintendo Entertainment System (NES) titles: Mega Man 3 and Mega Man 4.

The story of Mega Man III consists of the hero Mega Man battling the evil scientist Dr. Wily, who is using a converted oil platform in the middle of the ocean to draw energy from the Earth's core to power a new machine. After annihilating eight robots whom Wily had previously used, Mega Man makes his way to Wily's lab, where he encounters the mad doctor attempting to escape. A powerful robot designed specifically to destroy the hero, Punk, confronts Mega Man but is defeated. Mega Man chases Wily onto the oil platform (which emerges from the water as Wily's latest fortress) and halts his enemy's plans once again.