Batman: Arkham Asylum is a 2009 action-adventure game developed by Rocksteady Studios and published by Eidos Interactive in conjunction with Warner Bros. Interactive Entertainment. Based on the DC Comics superhero Batman and written by veteran Batman writer Paul Dini, Arkham Asylum was inspired by the long-running comic book mythos. In the game's main storyline, Batman battles his archenemy, the Joker, who instigates an elaborate plot to seize control of Arkham Asylum, trap Batman inside with many of his incarcerated foes, and threaten Gotham City with hidden bombs.

The game is presented from the third-person perspective with a primary focus on Batman's combat and stealth abilities, detective skills, and gadgets that can be used in combat and exploration. Batman can freely move around the Arkham Asylum facility, interacting with characters and undertaking missions, and unlocking new areas by progressing through the main story or obtaining new equipment. The player is able to deviate away from the main story to unlock additional content and collectible items. Combat focuses on chaining attacks together against numerous foes while avoiding damage, while stealth allows Batman to conceal himself around an area, using gadgets and the environment to silently eliminate enemies.

Development began at Rocksteady Studios in May 2007, with a 40-person team that expanded to 60 people by the project's conclusion after approximately 21 months. Among other sources, the game design was inspired by the Batman comics of Neal Adams and Frank Miller, as well as Grant Morrison and Dave McKean's graphic novel Arkham Asylum: A Serious House on Serious Earth. Built on Unreal Engine 3, Arkham Asylum's production underwent several variations, refining both gameplay such as the combat system, and the central story, resulting in the removal of plot elements and some of Batman's main enemies, who did not fit the tone of the rest of the game. Rocksteady began developing ideas for a sequel months before Arkham Asylum's completion, hiding hints to the sequel within the game.

Arkham Asylum was released worldwide for PlayStation 3 and Xbox 360 video game consoles in August 2009, followed by a Windows version. The game received critical acclaim, particularly for its narrative, atmosphere and combat, though some criticism was directed at its boss fights. Upon release, many reviewers called it the "greatest comic book game of all time." It won several awards, including Best Action Adventure game, Best Game, and Game of the Year from various media outlets, and it held the Guinness World Record for "Most Critically Acclaimed Superhero Game Ever". It has been cited as one of the greatest video games ever made. The game received a "Game of the Year Edition" in 2010, and a remastered version for the PlayStation 4 and Xbox One in 2016. A version for the Nintendo Switch was released in 2023.

Arkham Asylum's success launched the Batman: Arkham series, comprising video game sequels and spin-offs, comic books, merchandise, and movies, beginning in 2011 with its narrative sequel Arkham City.

Batman: Arkham Asylum is an action-adventure game viewed from the third-person perspective. The playable character is visible on the screen and the camera can be freely rotated around him. The player controls Batman as he traverses Arkham Asylum, a secure facility for the criminally insane located off the coast of Gotham City. The opening areas of the game are linear, serving as a tutorial for the moves and approaches available to the player. Once the player emerges onto the island they can freely explore the game world, although some areas remain inaccessible until certain milestones in the main story. Batman can run, jump, climb, crouch, glide from heights using his cape, and use his grapple gun to climb low structures or escape to higher ledges.

The player can use "Detective Vision"—a visual mode which provides contextual information, tinting the game world blue and highlighting interactive objects like destructible walls and removable grates, the number of enemies in an area and their status—such as their awareness of Batman's presence—and shows civilians and corpses. The mode is also used to follow footprints, investigate odors, and solve puzzles.

Batman has access to several gadgets which he can use to explore or fight. The batarang is a throwing weapon that can temporarily stun enemies or trigger remote devices. A remotely controlled version can be steered once thrown, and the sonic batarang can be used to attract the attention of specific enemies wearing monitoring collars, or detonated to knock a nearby enemy unconscious. Explosive gel can be used on weak walls and floors, and can be remotely detonated—sending rubble crashing onto an enemy. The line launcher can be used to traverse horizontal spans. The Batclaw—a grappling device—can be used to interact with remote objects such as vent covers or to grab enemies. The Cryptographic Sequencer is used to override security panels, open new paths, or disable various asylum functions. Some areas are inaccessible until Batman acquires the gadgets necessary to overcoming the obstacle. The player is encouraged to explore the game world away from the main game to find and solve riddles left by the Riddler—who hacks into Batman's communication system to challenge him with riddles. Objects can be collected, and some of the Riddler's puzzles require the player to find areas related to the answer to a riddle and scan it with "Detective Vision". The game world has 240 collectable items, such as Riddler trophies, chattering Joker teeth, interview tapes with some of Arkham's inmates, and cryptic messages left in the asylum by its founder Amadeus Arkham that discuss the facility's sinister history. The player is rewarded for solving riddles and finding collectibles with experience points and additional game content, including challenge maps that test the player's skill at the game's combat system, character biographies, and in-game statues of Arkham Asylum's characters.