Isabel Barreto Lobato (1948 – December 8, 1975) was an East Timorese politician, political activist, and member of Fretilin who was active in the movement for independence from Portugal. Barreto Lobato was a leading member of the Fretilin Women's Association at the time of East Timor's declaration of independence in November 1975. She was the wife of East Timor's first prime minister, Nicolau dos Reis Lobato, who held the office for nine days before the Indonesian invasion and occupation.