Metal Gear Solid is a 1998 action-adventure stealth video game developed and published by Konami for the PlayStation. It was directed, produced, and written by Hideo Kojima, and follows the MSX2 video games Metal Gear and Metal Gear 2: Solid Snake, which Kojima also worked on. It was unveiled at the 1996 Tokyo Game Show and then demonstrated at trade shows including the 1997 Electronic Entertainment Expo; its Japanese release was originally planned for late 1997, before being delayed to 1998.

Players control Solid Snake, a soldier who infiltrates a nuclear weapons facility to neutralize the terrorist threat from FOXHOUND, a renegade special forces unit. Snake must liberate hostages and stop the terrorists from launching a nuclear strike. Cinematic cutscenes were rendered using the in-game engine and graphics, and voice acting is used throughout.

Metal Gear Solid received critical acclaim. It sold more than seven million copies worldwide and shipped 12 million demos. It scored an average of 94/100 on the aggregate website Metacritic. It is regarded as one of the greatest and most important video games of all time and helped popularize the stealth genre and in-engine cinematic cutscenes. It was followed by an expanded version for PlayStation and Windows, Metal Gear Solid: Integral (1999), and a GameCube remake, Metal Gear Solid: The Twin Snakes (2004). The original game was re-released for PlayStation 3 and PlayStation Portable as a downloadable PSone Classics title on the PlayStation Network on March 21, 2008 in Japan, June 18, 2009 in North America, and November 19, 2009 in Europe; this version was later bundled alongside its sequels in the Metal Gear Solid: The Legacy Collection compilation in 2013 for PS3. The game was later ported by M2 and included as part of the Metal Gear Solid: Master Collection Vol. 1 compilation for Nintendo Switch, PlayStation 4, PlayStation 5, Windows and Xbox Series X/S in 2023. It produced numerous sequels, starting with Metal Gear Solid 2: Sons of Liberty in 2001, and media adaptations including a radio drama, comics, and novels.