Fortified Zone is a 1991 video game developed and published by Jaleco for the Game Boy. It was released in North America in September 1991.

Fortified Zone's plot follows two Mercenaries named Masato Kanzaki and Mizuki Makimura as they infiltrate a literal fortified zone, where they must take on mercenaries, soldiers, robots and monsters before destroying the central complex at the fortified zone's heart.

Fortified Zone allows the player to switch between two characters during game play. Each character has their own strengths and weaknesses: Masato (the male mercenary) uses all the special weapons, but cannot jump. Mizuki (the female mercenary) can jump, but cannot use the special weapons. A top-down shoot-'em-up, the game had four multi-room levels, titled 'Field', 'Jungle', 'Caves' and 'Complex'. At the end of each level the player faces a 'boss' character: a cannon installation, a supertank, a dragon, a bulldozer and a large assault vehicle as the final boss. Items that can be picked up in gameplay include medical packs, flamethrowers, hand grenades, rocket launchers, 3-way machine guns and chain guns.