Alpha Sigma Phi (ΑΣΦ), commonly known as A Sig, is an intercollegiate men's social fraternity. Founded in 1845 at Yale University in New Haven, Connecticut, it is the tenth oldest social fraternity in the United States.
Alpha Sigma Phi has 181 chapters with over 8,000 undergraduate students as active members and well over 72,000 living members. It is a member of the Fraternity Forward Coalition (FFC) and a former member of the North American Interfraternity Conference (NIC).