Gamma Sigma Chapter was organized on April 28, 1928 by six educators who were interested in furthering finer womanhood, scholarship, community service, and leadership. Soror Ola Mitchell was elected as the first chapter Basileus. Gamma Sigma is the oldest chapter of Sigma Gamma Rho Sorority, Inc. in the city of Houston and one of the oldest in Sigma Gamma Rho Sorority, Inc. 

The primary objectives of the Gamma Sigma Chapter are manifested by some of its community service projects: Project EyeSaver which provides glasses for underprivileged children; Bounty Ball fall celebration raising funds for community outreach programs; Annual Status of Women Luncheon which presents scholarship awards to graduating seniors; March of Dimes; Breast Cancer Awareness programs; Operation BigBookBag providing schools supplies and back packs for youth; Youth Symposium; Star of Hope Partnership; Wellness and Financial Empowerment Presentations; and Project Reassurance: Full Tummies and Dry Bottoms which provides baby items for unwed high schools students.

Gamma Sigma also advises a Rhoer Club, Philo Affiliates, and 3 undergraduates chapters in and around the Houston area: Epsilon Pi ( University of Houston), Lambda Lambda (Texas A & M University), and Kappa Mu (Sam Houston State University).