Sigma Kappa Sorority was founded by five young trailblazing women: Mary Caffrey Low, Elizabeth Gorham Hoag, Ida Fuller, Frances Mann, and Louise Helen Coburn.

Early women students were reluctantly admitted to colleges and were looked down upon by professors and male students alike. During this period of change for women, they were insulted, boycotted, and denied a share of the more prized college rights. They were courageous and determined to make a place for women in the collegiate world. This feeling inspired the formation of sororities on the basis of scholarship, friendship, mutual interests, and ideals.
Colby College in Waterville, Maine, was the first college in New England to admit women on an equal basis with men students. The first woman student was admitted in 1871, and for two years Mary Caffrey Low was the only woman student at Colby College. In 1873, four more young women from Maine, Elizabeth Gorham Hoag, Ida Fuller, Frances Mann, and Louise Helen Coburn were admitted to Colby and the five young women found themselves frequently together. During the school year of 1873-74, the five young women decided to form a literary and social society. They were told by the college administration that they needed to present a constitution and bylaws with a petition requesting permission to form Sigma Kappa Sorority. They began work during that year with an eager glow of enthusiasm. Their purpose at the outset was that the sorority should become what it is now, a national organization of college women. On November 9, 1874, the five young women received a letter from the faculty approving their petition. Thus, this date has since been considered our Founders' Day.
In our first constitution, chapter membership was limited to 25. The original group was known as Alpha chapter and as our sorority grew, Beta chapter and Gamma chapter were also established at Colby College. Early records indicate that the groups met together; but in 1893, the Sigma Kappa members decided intramural expansion was not desirable. They voted to fill Alpha chapter to the limit of 25 and to initiate no more into Beta and Gamma chapters. Eventually, the second and third chapters would vanish from Colby campus. Finally Sigma Kappas realized if the organization was going to continue to grow, it had to expand beyond the walls of Colby College.
The Theta Chapter of Sigma Kappa was chartered at the University of Illinois-Urbana Champaign in 1906.