Joo Bernardo "Nino" Vieira (Portuguese pronunciation: [uw bnau inu viej, ww -]; 27 April 1939 2 March 2009) was a Bissau-Guinean politician who was the President of Guinea-Bissau from 1980 to 1999, except for a three-day period in May 1984, and from 2005 to 2009.

After seizing power from President Lus Cabral in a military coup in 1980, Vieira ruled as part of the Military Council of the Revolution until 1984, when civilian rule was returned. Opposition parties were allowed in 1991, and Vieira won a multiparty presidential election in 1994. He was ousted at the end of the 19981999 civil war and went into exile. He made a political comeback in 2005, winning that year's presidential election.

Vieira was killed by soldiers on 2 March 2009, apparently in retaliation for a bomb blast that killed Guinea-Bissau's military chief General Batista Tagme Na Waie hours before. The military officially denied these allegations after unidentified Army officials claimed responsibility of Vieira for Na-Waie's death.Vieira described himself as "God's gift" to Guinea-Bissau during his tenure in office.