The Upsilon Sigma Phi is the oldest fraternity in Asia. Founded nebulously in 1918 by a group of liberal arts students of the University of the Philippines in Padre Faura, it was formally organized as the University Students Fraternity on November 19, 1920 at the Metropolitan Restaurant in Intramuros, Manila. Four months later, on March 24, 1921, the Greek letters “Upsilon Sigma Phi” were formally adopted.

Based in the University of the Philippines, it has had an unbroken and singular ssociation with the premier state university. There are no chapters outside of UP Diliman & Manila, and UP Los Banos. The fraternity counts among its ranks, national hero Sen. Benigno “Ninoy” Aquino, former Philippine Presidents Ferdinand E. Marcos and Jose P. Laurel, Sr., World War II martyr Chief Justice Jose Abad Santos, former Vice-Presidents Arturo M. Tolentino and Salvador H. Laurel, Senate President Gil J. Puyat, House Speaker Jose B. Laurel, Jr., Batasan Speakers Querube C. Makalintal and Nicanor E. Yñiguez, and Chief Justice Enrique M. Fernando among others.

On campus, the Upsilonians who have held the position of Student Council President were Enrique J. Corpuz, Wenceslao Q. Vinzons, Ramon Enriquez, Alberto Leynes, Jose B. Laurel, Jr., Roberto S. Bendicto, Sotero H. Laurel, Florante C. Roque, Hermogenes Concepcion, Jr., Antonio Azores, Troadio T. Quiazon, Jr., Delfin Villanueva, Emilio R. Espinosa, Jr., and Fernando C. Campos; University Student Union President Eric O. de Guia; and University Student Council Chairpersons Tristan A. Catindig, Manuel L. Ortega, and the current chairperson Michel Kristian R. Ablan.