António Maria de Sousa Horta e Costa (21 September 1859 – 5 September 1931) was a Portuguese nobleman, jurist, magistrate and politician.
He was the third son of Miguel António de Sousa Horta Almeida e Vasconcelos, 2nd Baron of Santa Comba Dão and second wife Maria da Glória da Costa Brandão e Albuquerque.