Antonio Fuentes Trillanes IV is a retired Philippine naval officer who also served as a senator of the Philippines from 2007 to 2019. He is known for his involvement in the Oakwood mutiny of 2003 and the Manila Peninsula siege in 2007 in protest against the Arroyo administration, and as a vocal critic of the Duterte administration.

On July 27, 2003, the Oakwood mutiny was staged by a group of about 300 armed defectors from the Armed Forces of the Philippines (AFP) and the Philippine National Police (PNP) led by Army Capt. Gerardo Gambala and Navy Lt. Senior Grade Antonio Trillanes IV against the Arroyo administration. The group forcibly seized and occupied Oakwood Premier in Glorietta, Makati for almost 20 hours. They expressed grievances against the government's supervision of the military, and demanded the resignation of Defense Secretary Angelo Reyes, PNP Director General Hermogenes Ebdane, and AFP Chief of Intelligence Service Victor Corpus; They also aired their grievances against the military establishment and anomalies on the AFP. The mutiny was covered heavily by the local press, who dubbed the group as "Magdalo" in reference to their insignia, which alludes to the Magdalo faction during the Philippine Revolution, despite the group officially calling themselves "Bagong Katipuneros". The mutiny ended after the government successfully negotiated with the group. Several prominent participants of the mutiny, including Trillanes and Gambala, were later charged.