Gaston Zavalla Ortigas (January 31, 1931 – August 31, 1990),[1] also known as Gasty was a Filipino professor, freedom fighter, agrarian reformer, entrepreneur, and peace advocate best known for his opposition to the Martial Law dictatorship of Ferdinand Marcos,[2] and for his later pursuit of a peace process between the post-dictatorship Philippine Government and various antidictatorship movements that did not give up their arms after Marcos was deposed in February 1986.

[1] After the declaration of Martial Law, Ortigas joined various organizations which were critical of Marcos's authoritarian regime, such as the Bishops-Businessmen's Conference and Movement for a Free Philippines (MFP), which was also led by Manglapus.

Eventually he had to flee the country to avoid falling into the hands of Marcos' armed forces.

[1] After the 1986 People Power Revolution, Ortigas returned to the Philippines and became an agrarian reform and peace process advocate.

[1] In his honor, the Ateneo de Manila University established the Gaston Z. Ortigas Peace Institute six months after his death.