Glenthorne High School is a non-selective mixed secondary school and sixth form located in the Sutton Common area of Sutton in the London Borough of Sutton, England. The school was first established in 1933 on Glastonbury Road in Sutton. It moved to the Sutton Common Road site in 1958, and at this time was called Sutton Common County Secondary Girls' School. The school changed its name to Glenthorne in 1982, and in 1993 it became coeducational.