José Ignacio Álvarez Thomas (15 February 1787 – 20 July 1857) was a South American military commander and politician of the early 19th century.

[2] Álvarez Thomas was born in Arequipa, Peru, and his family lived for some time in Lima.

However, soon after he openly opposed the politics of de Alvear's government, and his insurrection caused the resignation of the latter and resulted in a new election of a Supreme Director in the Constituting General Assembly, where he was designated interim Supreme Director from 20 April 1815, to 16 April 1816, in place of the elected José Rondeau,[4] who was absent on a military campaign in Peru.

When the Constituting General Assembly was dissolved in 1820, he was, as a still-influential member of the former leadership, sent to prison, but released after 19 days.

After his return to Buenos Aires, he was exiled and also spent some time in prison for his opposition against the government of Juan Manuel de Rosas.