In the spring of 1906, Miss Tommie Payne Duffy, Miss Eula Mae Jarnagin and Miss Grace McCallie received a charter for a school founded on Christian principles, to prepare girls for college through academic training and to fit them for useful lives in the home and in the affairs of the communities in which they live by instilling in them high principles of honesty, integrity, and consideration for others. Begun in Miss McCallie's home at 106 Oak Street, Girls Preparatory School opened for the girls of Chattanooga on September 12, 1906.
Within nine years, the school had outgrown its space and moved to 611 Palmetto Street where the school expanded its academic curriculum and built its first gym. The founders of the school did not just change the course of girls' education and athletics for their students; they were influential in beginning the city's first basketball league for girls and the first academic contest to include girls. Though Miss McCallie died unexpectedly in 1918, Misses Duffy and Jarnagin continued as heads of the school until July 30, 1945, at which time the Board of Trustees moved to incorporate the school.
On September 26, 1947, GPS opened the new school year on its present campus with a new building consisting of fourteen classrooms, a study hall, library, and cafeteria. A gymnasium was constructed in 1953 and a Junior School building in 1959. GPS continued to grow with the 1973 addition of the Science and Fine Arts building and the Group Meeting Room, now called the Evans Center. Continuing one of the original practices of the school, GPS offered girls the opportunities to participate in athletic teams and physical education, adding a field house, dance studio, and additional gymnasium in 1978. Due to continually expanding academics at GPS, a new two-story building to house an expanded library and language lab facility was built in 1983. The 1991 completion of the C.G. Mills Complex, with its Frierson Theater, natatorium, Caldwell Fitness Center, new gymnasium, and administrative offices, changed the face of the campus again. In the spring of 2007, another groundbreaking began the construction of a new dining hall and C. Ben Harnsberger Student Center.
Named a National School of Excellence on May 13, 1991, GPS remains a school which receives national recognition due to its strong academics, technological initiatives, and competitive athletics. The Davenport Middle School building, completed in 1999, allowed for the addition of a sixth grade class to the school.
With the school's celebration of its Centennial in 2005-2006, the founders' goal of providing the best possible education to girls is still the resounding aim of the school's faculty, staff, and Board of Trustees.