| Tião Viana | |
| Office: | 17th Governor of Acre |
| Term Start: | 1 February 2011 |
| Term End: | January 1, 2019 |
| Predecessor: | Binho Marques |
| Successor: | Gladson Cameli |
| Office1: | Senator for Acre |
| Term Start1: | 1 February 1999 |
| Term End1: | 21 December 2010 |
| Predecessor1: | Flaviano Melo |
| Successor1: | Aníbal Diniz |
| Office2: | President of the Federal Senate |
| Term Start2: | 15 October 2007 |
| Term End2: | 11 December 2007 |
| Predecessor2: | Renan Calheiros |
| Successor2: | Garibaldi Alves Filho |
| Birth Date: | 9 February 1961 |
| Birth Place: | Rio Branco, AC, Brazil |
| Alma Mater: | University of Brasília (UnB) Federal University of Triângulo Mineiro (UFTM) |
| Spouse: | Marlucia Cândido |
| Occupation: | Physician, Politician |
Sebastião Afonso Viana Macedo Neves, better known as Tião Viana (Rio Branco, February 9, 1961), is a doctor and Brazilian politician. He was formerly Governor of Acre and is a member of the Workers' Party. He served as interim President of the Senate in 2007.[1]