António Mendes Belo (18 June 1842 – 5 August 1929) was a Portuguese prelate of the Catholic Church, who served as Patriarch of Lisbon from 1907 until his death.

António Mendes Belo was born at São Pedro, Gouveia, (District of Guarda), Portugal.

He was son of Miguel Mendes Belo and wife Rosalina dos Santos de Almeida da Mota.

From 1865 to 1884 he was vicar general of Funchal and from 1865 to 1871, professor of theology at the Seminary of Pinhel[a] He did pastoral work in the parish of Espinheiro.

He was appointed titular archbishop of Mitylene and Auxiliary bishop of Lisbon on 24 March 1884 by Pope Leo XIII.