Captain Prince Antônio Gastão of Orléans-Braganza MC (Portuguese: Antônio Gastão de Orléans e Bragança; 9 August 1881 – 29 November 1918) was a Brazilian prince who served in the forces of the British Empire during World War I. Antônio was born in Paris, the third and last son of Isabel, Princess Imperial of Brazil, and her husband Gaston of Orléans, Count of Eu.

[1] His father was a grandson of the last king of France, Louis Philippe I, and his mother was the eldest daughter and heiress of Emperor Pedro II of Brazil.

[2] His full name was Antônio Gastão Luiz Filipe Francisco de Assis Maria Miguel Rafael Gabriel Gonzaga;[1] his family affectionately called him "Totó".

[8] He was aide-de-camp to the commander of the Canadian Cavalry Brigade, Brigadier-General Seely,[9] from February 1917[10] until May 1918,[11] and then was seconded for duty with the War Office in July.

[12] Antônio died from injuries sustained in an air crash at Edmonton, London, shortly after the end of the war.