Sigma Mu Sigma (ΣΜΣ) is a college fraternity founded in 1921 at Tri-State University. Sigma Mu Sigma was historically an all-male social fraternity open originally to Master Masons, and later open to all undergraduate male students. As a national fraternity, Sigma Mu Sigma dissolved in 1935 when it was absorbed by Tau Kappa Epsilon. Sigma Mu Sigma was later revived, developed another dozen chapters, and several of these were absorbed by Kappa Sig, Acacia and others. A few remaining chapters of Sigma Mu Sigma transformed into a co-ed service fraternity in 1984. ΣΜΣ currently has two active chapters.