GATO is a real-time submarine simulator first published in 1984 by Spectrum HoloByte for MS-DOS. It simulates combat operations aboard the Gato-class submarine USS Growler (SS-215) in the Pacific Theater of World War II. GATO was later ported to the Apple IIe, Atari ST, and Macintosh. In 1987 Atari published a version on cartridge for the Atari 8-bit family, to coincide with the launch of the Atari XEGS.