Beta Iota Chapter of Alpha Gamma Delta began as Psi Omega, local sorority at Eastern Illinois University, on October 19, 1959. The first three founders of the group were Judith Langley, Barbara Buck, and Gwen Gibson.

On January 19, 1960, Alpha Gamma Delta Grand President, Lou Good Vogelsang, visited Eastern, and Psi Omega signed an agreement under which it would begin pledging for affiliation with Alpha Gamma Delta.
On March 2, 1960, Psi Omega became a pledging chapter of Alpha Gamma Delta. Sigma Undergraduate Chapter, from the University of Illinois, initiated fifteen undergraduates and two alumnae as Beta Iota Chapter in May 1960. The initiation program was held in Pemberton Hall with Lou Vogelsang, Grand President, Mary Jane Grimes Flommer, Executive Secretary, and several undergraduate members of Sigma participating. The undergraduates who were initiated were: Judith Langley, Broadview; Barbara Buck, Hazel Crest; Kate Stine, Edwardsville; Kay Griffey, Kankakee; Diane Doran, Kankakee; Flo Krause, North Chicago; Gwen Gibson, Homewood; Cynthia Helton, Brocton; Marilyn Foote, Robinson; Nancy Shaw, Paris; Mary Maxwell, Longview; Sandy Bird, Casey. The two alumnae initiated were: Lafell Livesay, Mattoon, and Olive Alexander, Charleston.

On September 24, 1960, Lou Vogelsang officially installed Beta Iota as the 86th chapter of Alpha Gamma Delta. Beta Iota became the 10th Greek Organization on Eastern's campus.

Barbara Buck was the first Chapter President. Meetings were held in the basement of Pemberton Hall, until a sorority house was found. The chapter has had four different sorority houses in the span of 30 years. In 1991, Alpha Gamma Delta moved to its present location, Eastern Illinois University's Greek Court.