Wallington is a town in the London Borough of Sutton, in South London, England. It is 9.7 miles (15.6 km) south south-west of Charing Cross. Before the Municipal Borough of Beddington and Wallington merged into the London Borough of Sutton in Greater London in 1965, it was part of the county of Surrey. Wallington is a post town in the SM postcode area. The town is home to three of the borough's five grammar schools. The London Borough of Sutton is a top performing borough for education in the United Kingdom.