Assassin's Creed Valhalla is a 2020 action role-playing game developed by Ubisoft Montreal and published by Ubisoft. It is the twelfth major installment in the Assassin's Creed series, and the successor to 2018's Assassin's Creed Odyssey. Principally set in the years 872–878 AD, the game recounts a Viking fantasy story during their expansions into the British Isles. Players control Eivor Varinsdottir, a Viking raider who, while attempting to establish a new Viking clan in England, becomes embroiled in the centuries-old conflict between the Assassin Brotherhood, who fight for peace and liberty, and the Templar Order, who desire peace through control. The game also includes a framing story, set in the 21st century, which follows Layla Hassan, an Assassin who relives Eivor's memories so as to find a way to save the Earth from destruction.

Development of the game began in 2017, around the release of Assassin's Creed Origins. Ubisoft Montreal led its three-year development with help from fourteen other Ubisoft studios worldwide, as well as Sperasoft. Numerous people involved in the development of past Assassin's Creed games returned for Valhalla, including Ashraf Ismail, who served as the creative director for Assassin's Creed IV: Black Flag (2013) and Origins; Darby McDevitt, the lead writer for Black Flag and Assassin's Creed: Revelations (2011) and co-writer of Assassin's Creed Unity (2014); and composers Jesper Kyd and Sarah Schachner, who composed the game's soundtrack alongside musician Einar Selvik. Similarly to Origins and Odyssey, the team conducted extensive research into the time period to make the game world as historically accurate as possible, and drew inspiration from Norse mythology for certain narrative elements. The team also sought to address some issues found by players with Odyssey, such as its over ambitiousness, small focus on the Assassin-Templar conflict, and the absence of traditional Assassin's Creed gameplay elements like social stealth.

Valhalla was released for PlayStation 4, Windows, Xbox One, Xbox Series X and Series S, and Stadia on November 10, 2020, with the PlayStation 5 version following on November 12. It received generally positive reviews, with praise for the narrative, characters, voice acting, visuals, soundtrack, world-design and the interconnectivity of activities, while being criticized for its length, technical issues, and repetitive structure. The game had the biggest launch in the Assassin's Creed series to date, selling the most copies within its first week and becoming the second most profitable Ubisoft title of all time. Ubisoft supported Valhalla extensively with two years of additional content, including both free and paid story expansions, game modes, and events. The game was followed by 2023's Assassin's Creed Mirage, which features a historical setting in Baghdad during the Islamic Golden Age and follows Basim Ibn Ishaq, a major supporting character from Valhalla.