Phi Omega Sigma is a collegiate social and service fraternity/sorority in the Philippines.
Phi Omega Sigma may also refer to:
Phi Omega Sigma former fraternity at the College of Wooster Phi Omega Sigma Christian Fraternity, Inc., a co-educational fraternity in Missouri State University Phi Omega Sigma, a women's social club in Oklahoma Baptist University Phi Omega Sigma, a housing group in Grove City College Phi Omega Sigma, a fraternity at the University of Puerto Rico at Arecibo