Assassin's Creed IV: Black Flag is a 2013 historical action-adventure open world video game developed by Ubisoft Montreal and published by Ubisoft. It was released for the PlayStation 3, Xbox 360 and Wii U in October 2013 and for the PlayStation 4, Windows and Xbox One in November 2013.

It is the sixth major installment in the Assassin's Creed series, a sequel to 2012's Assassin's Creed III's modern story and a prequel to its historical storyline. The story is set in the early 18th century Caribbean during the Golden Age of Piracy, and follows notorious pirate Edward Kenway, grandfather of Assassin's Creed III protagonist Ratonhnhaké:ton, who stumbles upon the conflict waged by the Assassins and Templars. Unlike previous games, gameplay elements focus more on ship-based exploration in the open world map, while also retaining the series' third-person land-based exploration, melee combat, and stealth system. Multiplayer also returns, albeit with only land-based modes and settings.

Assassin's Creed IV: Black Flag received positive reviews, with critics praising the open world gameplay, side-quests, graphics and naval combat. The story received a mixed response, while criticism fell on aspects of the story missions which were considered repetitive. The game received several awards and nominations, including winning the Spike VGX 2013 award for Best Action Adventure Game.