Sandra Rees was born in Melbourne in 1942, and moved to Sydney in 1952 as her father, an Army officer, was appointed to the School of Military Engineering at Casula. Sandra earned a Bachelor of Science with Honours in 1963 and Master of Science in 1965, both from the University of Sydney. During this time she studied the structure and function of the visual system in the Department of Physiology, chaired by Professor Peter Bishop.