Count of Santa Cruz (in Portuguese Conde de Santa Cruz) was a Portuguese title of nobility created by a royal decree of King Philip II of Portugal, also known as Philip III of Spain, dated from October 3, 1593, and granted to Francisco de Mascarenhas (1530-1608), nephew of Dom Pedro de Mascarenhas, 6th Viceroy of Portuguese India.
Through a remarkable marriage policy, this family inherited several other titles and estates, such as Marquess of Gouveia in 1686, and Duke of Aveiro in 1745.
During the Brazilian Empire, there was also a title of Count of Santa Cruz, later upgraded to Marquis of Santa Cruz, granted to Romualdo António de Seixas (1787-1860), and it should not be confused with this Portuguese title.