Ubisoft Entertainment SA (/ˈjuːbisɒft/; French: [ybisɔft]; formerly Ubi Soft Entertainment SA) is a French video game publisher headquartered in Saint-Mandé with development studios across the world. Its video game franchises include Anno, Assassin's Creed, Driver, Far Cry, Just Dance, Prince of Persia, Rabbids, Rayman, Tom Clancy's, and Watch Dogs.

Ubisoft is led by chairman and CEO Yves Guillemot. The company first achieved commercial and critical success with their 1995 platform game Rayman. In 1996, the company began to expand to other parts of the world, opening studios in Annecy, Shanghai, Montreal and Milan. In recent years, Ubisoft has struggled financially, with a strong decline in revenue in 2024, and laying off 185 employees in 2025.

By the 1980s, the Guillemot family had established itself as a support business for farmers in the Brittany province of France and other regions, including into the United Kingdom. The five sons of the family – Christian, Claude, Gérard, Michel, and Yves – helped with the company's sales, distribution, accounting, and management with their parents before university.

All five gained business experience while at university, which they brought back to the family business after graduating. The brothers came up with the idea of diversification to sell other products of use to farmers; Claude began with selling CD audio media. Later, the brothers expanded to computers and additional software that included video games.

In the 1980s, they saw that the costs of buying computers and software from a French supplier were more expensive than buying the same materials in the United Kingdom and shipping to France, and came upon the idea of a mail-order business around computers and software. Their mother said they could start their own business this way as long as they managed it themselves and equally split its shares among the five of them.

Their first business was Guillemot Informatique, founded in 1984. They originally only sold through mail order, and then were getting orders from French retailers, since they were able to undercut other suppliers by up to 50% of the cost of some titles. By 1986, this company was earning about 40 million French francs (roughly US$5.8 million at that time). In 1985, the brothers established Guillemot Corporation for similar distribution of computer hardware. As demand continued, the brothers recognised that video game software was becoming a lucrative property and decided that they needed to get into the industry's development side, already having insight on the publication and distribution side.

Ubi Soft (formally named Ubi Soft Entertainment S.A.) was founded by the brothers on 28 March 1986. The name "Ubi Soft" was selected to represent "ubiquitous" software.

Ubi Soft initially operated out of offices in Paris, moving to Créteil by June 1986. The brothers used the chateau in Brittany as the primary space for development, hoping the setting would lure developers, as well as to have a better way to manage expectations of their developers. The company hired Nathalie Saloud as manager, Sylvie Hugonnier as director of marketing and public relations, and programmers, though Hugonnier had left the company by May 1986 to join Elite Software. Games published by Ubi Soft in 1986 include Zombi, Ciné Clap, Fer et Flamme, Masque, and Graphic City, a sprite editing program. As their first game, Zombi had sold 5,000 copies by January 1987. Ubi Soft also entered into distribution partnerships for the game to be released in Spain and West Germany. Ubi Soft started importing products from abroad for distribution in France, with 1987 releases including Elite Software's Commando and Ikari Warriors, the former of which sold 15,000 copies by January 1987. In 1988, Yves Guillemot was appointed as Ubi Soft's chief executive officer.