Carlos Antonio Santos-Viola FPIA (born Carlos Santos-Viola y Antonio; April 8, 1912 – July 31, 1994) was an architect in the Philippines. He is best known for designing and building churches for the Iglesia ni Cristo (INC) religious group. Carlos was born in San Miguel, Bulacan and one of six children to Melecio de Guzman Santos and Miguela Magpitang Antonio. Santos-Viola worked in the office of Juan Nakpil after graduating. There he met Juan's youngest sister, Caridad, his future wife and mother to his children: Rosario, Milagros, Paz, Lourdes and Carlos, Jr.