| José Mascarenhas Barreto | |
| Marquis of Fronteira, Count of Coculim | |
| Spouse: | Maria Constança da Câmara |
| Succession: | Marquis of Fronteira |
| Full Name: | José Trasimundo Mascarenhas Barreto |
| Noble Family: | Mascarenhas Barreto |
| Father: | João José Luís de Mascarenhas Barreto, 6th Marquis of Fronteira |
| Mother: | Leonor Benedita de Oyenhausen de Almeida |
| Birth Date: | 11 January 1802 |
| Birth Place: | Lisbon, Kingdom of Portugal |
| Death Date: | 19 February 1881 |
José Trasimundo Mascarenhas Barreto, 7th Marquis of Fronteira (Lisbon; 11 January 1802 — 19 February 1881); was a Portuguese nobleman and politician.
José Trasimundo Mascarenhas Barreto was born in Lisbon on 11 January 1802 to João José Luís de Mascarenhas Barreto, 6th Marquis of Fronteira, and Leonor Benedita de Almeida e Almeida, daughter of Leonor de Almeida Portugal, 4th Marquise of Alorna.
He married on February 14, 1821 Maria Constança da Câmara, Lady of the Order of Saint Isabel, and maid of honour of Queen Maria II of Portugal.
He had only one daughter, D. Maria Mascarenhas Barreto.