Fidel V. Agcaoili (August 8, 1944 – July 23, 2020), also known as Ka Fidel, was a Filipino activist and revolutionary. He was a member of the Communist Party of the Philippines' Central Committee, along with Jose Maria Sison and during the Marcos dictatorship. In 1974, he was arrested and became the longest detained political prisoner under Marcos, being imprisoned for 11 years. On his release, Agcaoili founded the Samahan ng mga Ex-Detainee Laban sa Detensyon at Aresto (SELDA), a prisoners' rights organization.