Call of Duty: Black Ops is a first-person shooter video game developed by Treyarch, published by Activision and released worldwide on November 9, 2010 for Microsoft Windows, Xbox 360, PlayStation 3, and Wii consoles, with a separate version for Nintendo DS developed by n-Space. Announced on April 30, 2010, the game is the seventh installment of the Call of Duty series. It is also the first to be set in the Cold War and the fifth to be set in World War II. It is the third in the series to be developed by Treyarch, and is a sequel to the developer's Call of Duty: World at War.

Within 24 hours of going on sale, the game sold more than 5.6 million copies, 4.2 million in the U.S. and 1.4 million in the UK, breaking the record set by its predecessor Modern Warfare 2 by some 2.3 million copies. A subtitled version was released in Japan on November 18, 2010. A Japanese-dubbed version was released on December 16, 2010. After six weeks on release, Activision reported Black Ops had earned $1 billion in sales. On August 3, 2011, Activision confirmed that the game had sold over 25 million copies worldwide, making it the best-selling game of all time in the US, UK and Europe. On April 28, 2012, it was leaked that the sequel, Call of Duty: Black Ops II, will be released on November 13, 2012.

A black operation or black op is a covert operation typically involving activities that are highly clandestine and often outside of standard military protocol or even against the law.

Black ops missions often fit into the plausible deniability category, in which there is no claim of responsibility for the action, and/or a false flag operation is used to give the appearance that another actor was responsible, or – most often – black operations involve extensive arrangements so as to be able to hide the fact that the black operation ever occurred. Black military operations, or paramilitary operations, can be used by various secret services to achieve or attempt to achieve an unusually sensitive goal. The methods used in black operations are also used in unconventional warfare. Depending on the precise situation in a given case, and the level of authoritarianism of the national government or other responsible party, some tasks will be conducted as black operations, while there are usually other activities that can be admitted openly. Black operations may include such things as assassination, sabotage, extortion, spying on allied countries or one's own citizens, kidnapping, supporting resistance movements, torture, use of fraud to obtain funds, use of child soldiers, human experimentation, trafficking in contraband items, and false flag operations, among others.

Call of Duty is a first-person and third-person shooter video game series franchise. The series began on the PC, and later expanded to consoles and handhelds. Several spin-off games have also been released. The earlier games in the series are set primarily in World War II; starting with Modern Warfare, set in modern times, the series has shifted focus away from World War II. Modern Warfare was followed by Modern Warfare 2, set in modern times, and Black Ops, set during the Cold War. Modern Warfare 3, also set in modern times (as the name suggests) was released on 8 November 2011.

The Call of Duty games are published and owned by Activision and published for Apple OS X by Aspyr Media. Most have been developed primarily by Infinity Ward and Treyarch; some games have been developed by Gray Matter Interactive, Spark Unlimited, Pi Studios, Amaze Entertainment, Rebellion Developments, and n-Space. The games use a variety of engines, including the id Tech 3, the Treyarch NGL, and the IW 5.0. Other products in the franchise include a line of action figures designed by Plan-B Toys, a card game created by Upper Deck, and a comic book mini-series published by WildStorm.