Metal Gear Solid (メタルギアソリッド) (commonly abbreviated as MGS) is a stealth action video game directed and written by Hideo Kojima. The game was developed by Konami Computer Entertainment Japan and first published by Konami in 1998 for the PlayStation video game console. It is the sequel to Kojima's early MSX2 computer games Metal Gear and Metal Gear 2: Solid Snake. The game featured an unprecedented amount of cinematic cut scenes rendered using the in-game engine and graphics, as well as voice acting in numerous codec sequences.

The story of Metal Gear Solid takes place in 2005, south-west of Alaska in the Bering sea. It follows Solid Snake, a retired soldier who infiltrates a nuclear weapons disposal facility to neutralize the terrorist threat from FOXHOUND, a renegade special forces unit. Snake must liberate two hostages, the head of DARPA and the president of a major arms manufacturer, confront the terrorists, and stop them from launching a nuclear strike.

Metal Gear Solid was well-received, shipping more than six million copies, and scoring an average of 94 out of 100 on the aggregate website Metacritic. It is recognized by many critics as one of the best and most important games of all time, heralded as the game which made the stealth genre popular. The commercial success of the title prompted the release of an expanded version for the PlayStation and PC, titled Metal Gear Solid: Integral; and a remake, Metal Gear Solid: The Twin Snakes was later released for the Nintendo GameCube. The game has also spawned numerous sequels, prequels, a port of the game to Windows PCs and spin-offs, including several games, a radio drama, comics, and a novel. On June 18, 2009, the original game was released on the PlayStation Network for use on the PlayStation 3 and PlayStation Portable.