Mega Man Zero 4 is a video game developed by Inti Creates and Natsume and published in 2005 by Capcom for the Game Boy Advance (GBA) handheld. It is the fourth and final installment of the Mega Man Zero subseries of the Mega Man franchise and is set several months after the events of Mega Man Zero 3. The European version featured a completely different logo, which was also used on Mega Man X7, Mega Man X8, Mega Man X: Command Mission, Mega Man Zero 2, Mega Man Zero 3, Mega Man Network Transmission, Mega Man Battle Chip Challenge, Mega Man Battle Network 3, Mega Man Battle Network 4, and Mega Man Battle Network 5. The game deals with Dr. Weil's reign over Neo Arcadia in which humans, who have been reduced to second-rate citizens, begin to escape in large numbers to the last-known livable location on the planet, Area Zero, beginning a conflict between the two groups. The effects of this war eventually drive Zero and the Resistance to protect Area Zero and its inhabitants from Dr. Weil.

Since its original release, it has been brought to the Nintendo DS family of systems as part of the Mega Man Zero Collection in 2010 and the Wii U's Virtual Console in 2016. In February 2020, it was released on PC (Steam), Nintendo Switch, PlayStation 4, and Xbox One as part of the Mega Man Zero/ZX Legacy Collection.