Mortlake is a suburban district of the London Borough of Richmond upon Thames on the south bank of the River Thames between Kew and Barnes. Historically it was part of Surrey and until 1965 was in the Municipal Borough of Barnes. For many centuries it had village status and extended far to the south, to include East Sheen and part of what is now Richmond Park. Its Stuart and Georgian history was economically one of malting, brewing, farming, watermen and the Mortlake Tapestry Works (1617–1704), Britain's most important producer. A London landmark, the former Mortlake Brewery or Stag Brewery, is on the edge of Mortlake.

The London Borough of Richmond upon Thames in southwest London, England, forms part of Outer London and is the only London borough on both sides of the River Thames. It was created in 1965 when three smaller council areas amalgamated under the London Government Act 1963. It is governed by Richmond upon Thames London Borough Council and is divided into nineteen wards. The population is 198,019 and the major settlements are Barnes, East Sheen, Mortlake, Kew, Richmond, Twickenham, Teddington and Hampton.