Phi Kappa Theta (ΦΚΘ), commonly known as Phi Kap, is a national social fraternity that has over 50 active chapters and colonies at universities across the United States. The fraternity was founded on April 29, 1959 at Ohio State University in Columbus, Ohio with the agreed upon merger of two older Catholic Christian fraternities, Phi Kappa and Theta Kappa Phi. Phi Kappa was founded exactly 70 years prior in 1889 at Brown University in Providence, Rhode Island, while Theta Kappa Phi was founded later in October 1919 at Lehigh University in Bethlehem, Pennsylvania.
Although Phi Kappa Theta membership is not currently exclusive to any one faith, it and the two fraternities that united to form it were historically Catholic fraternities.