Kappa Alpha Theta (ΚΑΘ), commonly referred to simply as Theta, is an international women’s fraternity founded on January 27, 1870, at DePauw University in Greencastle, Indiana. It was the first Greek-letter fraternity established for women. The fraternity (the term "sorority" had not yet been invented) was founded by four female students, Bettie Locke Hamilton, Alice Allen Brant, Bettie Tipton Lindsey, and Hannah Fitch Shaw. The organization has 147 chapters at colleges and universities in the United States and Canada. The organization was the first women's fraternity to establish a chapter in Canada. Theta's total living initiated membership, as of 2020, was more than 250,000. There are more than 200 alumnae chapters and circles worldwide.

Kappa Alpha Theta is a member of the National Panhellenic Conference (NPC), an umbrella organization that encompasses 26 social sororities found throughout North America. The organization's own headquarters are located in Indianapolis, Indiana.