Delta Sigma Delta (ΔΣΔ), founded on November 15, 1882, is the oldest and largest of the international professional dental fraternities,[1] pre-dating Xi Psi Phi (1889), Psi Omega (1892) and Alpha Omega (1907).

Two dental students, Lou Mitchell and Chas Howard, at the University of Michigan School of Dentistry in Ann Arbor were invited to join Nu Sigma Nu, a medical fraternity. However, they decided to decline as their intentions were to create a dental fraternity. On November 15, 1882, seven dental students met at Mrs. Slattery's boarding house at #10 North State St., Ann Arbor, Michigan, and founded the first dental fraternity in the world. For a name, they transposed the initials of the D.D.S. degree, which they were soon to receive, to D.S.D. and substituted the Greek letters DSD for the English. Thus, Delta Sigma Delta was born and the new chapter became known as the Alpha Chapter.

After graduation these men became scattered in all directions but they strongly desired to maintain their associations and friendships of college days. This was the beginning of the Supreme (or Alumni) Chapter, which was founded in Detroit, MI after their graduation from dental school in 1895.

Soon a second chapter, Beta, was formed at the Chicago College of Dental Surgery in 1885 by Dr. L.L. Davis who had migrated there to practice dentistry. Then a third, Gamma, at Harvard was begun.

Undergraduate Chapters are located in dental schools and Graduate Chapters are located throughout the United States and Canada, as well as Europe, Asia, and Australia. The Supreme Council is designated as the administrative or governing body of the fraternity.

As of 2016 there are 33 active chapters.