Uno is an island in the Bissagos archipelago off the coast of Guinea-Bissau, in the Atlantic Ocean. The land area is , with a population of 3,324 (2009).
Uno and the Bissagos Islands are part of the Boloma Bijagós Biosphere Reserve, a UNESCO Biosphere Reserve designated in 1996.
The Uno Sector, part of the Bolama Region, covers Uno and the nearby islands of Eguba, Orango, Unhocomo, Unhocomozinho and Uracane. The sector's population is 6,751 (2009 census).