Antônio Augusto Borges de Medeiros (19 November 1863 – 25 April 1961) was a Brazilian lawyer and politician, and the President of Rio Grande do Sul for a total of 35 years (1898–1908 and 1913–1928), during the period of Brazilian history known as the República Velha.
Medeiros was born in Caçapava do Sul.
He ran in the presidential election of 1934, but was defeated by President Getúlio Vargas.