Mário de Sousa, 1st Count of Sousa (1826—1896) was a Portuguese admiral, nobleman, and former Catholic priest. He held the office of Portuguese Navy chief during the reign of King Luís I of Portugal. A former priest, he later joined the Royal Navy of Portugal and worked in Africa to convert natives to the Catholic faith. He later worked his way up to the rank of admiral of the fleet and became the Navy commander. The Count was replaced in 1889, upon the death of King Luís, by Adriano de Moura.