Call of Duty: Black Ops is a 2010 first-person shooter game developed by Treyarch and published by Activision. It was released worldwide in November 2010 for Microsoft Windows, the PlayStation 3, Wii, and Xbox 360, with a separate version for Nintendo DS developed by n-Space. Aspyr later ported the game to OS X in September 2012. It is the seventh title in the Call of Duty series and a sequel to Call of Duty: World at War.

Set in the 1960s during the Cold War, the game's single-player campaign follows CIA operative Alex Mason as he attempts to recall specific memories to locate a numbers station set to instruct Soviet sleeper agents to deploy chemical weapons across the United States. Locations featured in the game include Cuba, the Soviet Union, the United States, South Vietnam, Hong Kong, Canada, and Laos. The multiplayer component of Black Ops features multiple objective-based game modes that are playable on 14 different maps included with the game. Improvements to loadout options and killstreak rewards are made. A form of virtual currency, COD Points, allows players to purchase weapons and customization options for their in-game character, as well as attachments and customization options for their weapon.

Development for the game began in 2010. Whereas Treyarch worked on both World at War and the tie-in video game for the James Bond film Quantum of Solace simultaneously, they focused specifically on Black Ops during this development cycle. Different teams within Treyarch focused on a certain game mode. Black Ops runs an enhanced version of the IW 3.0 engine used in World at War. The improvements made allowed for bigger campaign levels to be made as well as enhanced lighting. Music was composed by Sean Murray, with licensed music by the Rolling Stones, Creedence Clearwater Revival, and Eminem appearing in the game. Avenged Sevenfold also recorded an original song for the game as well. The marketing of the game began in April 2010.

The game received positive reviews from critics with praise for its story, voice-acting, darker tone and multiplayer modes, although some criticized it for its linear gameplay and technical issues. Among other awards and nominations, Call of Duty: Black Ops was nominated for Game of the Year by numerous media outlets and award shows, including the Interactive Achievement Awards, British Academy Games Awards, and Spike Video Game Awards. Within 24 hours of going on sale, the game had sold more than 5.6 million copies, breaking the record set by its predecessor Modern Warfare 2 by some 2.3 million copies. The game had sold over 25 million copies worldwide, making it, at the time, the best selling game of all time in the United States, and it remains one of the best-selling games of all time. A sequel, Call of Duty: Black Ops II, was released in 2012. Call of Duty: Black Ops Cold War, set between Black Ops and Black Ops II, was released in 2020.

Black Ops is a first-person shooter, retaining the same gameplay mechanics as previous Call of Duty titles. The player assumes the role of a foot soldier who can wield various firearms (only two of which can be carried at once), throw grenades and other explosives, and use other equipment as weapons. A player close enough to an enemy can kill with one knife blow. A character can take three stances: standing, crouching, or prone. Each affects the rate of movement, accuracy, and stealth. The player can drop to the prone stance from the standing stance while running (colloquially known as "dolphin diving"), and can momentarily sprint before stopping.

The screen glows red to indicate damage to a player's health, which regenerates over time. When the character is within the blast radius of a live grenade, an on-screen marker indicates where it is in relation to the player, helping the player to move away or to throw it back. Among the weapons new to the series in Black Ops are crossbows that shoot typical bolts or explosive ammunition, a kind of shotgun that fires Dragon's Breath rounds and ballistic knives.

The player assumes the role of various characters during the single-player campaign, changing perspectives throughout the story. The playable characters are covert operatives conducting black operations behind enemy lines. Each mission features a series of objectives that are displayed on the heads-up display, which marks the direction and distance towards and from such objectives as it has been in the earlier versions. The player is accompanied by friendly troops throughout the game. Although the game is primarily a first-person shooter, certain levels feature sequences where the player pilots a Hind helicopter and guides friendly troops from a SR-71 Blackbird reconnaissance aircraft. In addition, the campaign features several scripted cinematic moments.

The online multiplayer gameplay of Black Ops consists of one of several styles of team-based action, depending on the chosen game mode. For example, in Team Deathmatch the team with the most kills wins, while in Capture the flag, players take the other team's flag and return it to their base. Additionally, there is Free For All in which players are not separated into teams. Not including downloadable maps released after the game´s launch, there are 14 different maps.