Count of Viana (do Alentejo) was a Portuguese title of nobility granted to D. João Afonso Telo, who was the second son of João Afonso Telo, 4th Count of Barcelos^[1] and a cousin of Queen Leonor Teles, by King Ferdinand I of Portugal pursuant to a royal decree dated 19 March 1373.

The first count belonged to one of the most powerful families among the Portuguese nobility and even though he supported Beatrice of Portugal's party during the 1383-1385 Crisis, the county of Viana (do Alentejo) was inherited by his descendants.

List of the Counts of Viana (do Alentejo)

1. João Afonso Telo,^[1] (c. 1330-1384);
2. Pedro de Menezes (c.1370-1437), his son, also 1st Count of Vila Real;
3. Duarte de Menezes (1414–1464), his natural son, also 2nd Count of Viana (da Foz do Lima);
4. Henrique de Menezes (c.1450-1480), his son, also 3rd Count of Viana (da Foz do Lima) and 1st Count of Loulé.