The London Borough of Richmond upon Thames () is an Outer London borough formed in 1965 from the merger of three older boroughs. These were the Municipal Borough of Richmond and the Municipal Borough of Barnes, situated south of the Thames which was, until 1965, part of Surrey, and the Municipal Borough of Twickenham on the northern, Middlesex bank of the Thames. In this way it is the only London borough to straddle the River Thames.
The population is 198,019 and the major communities are Barnes, East Sheen, Mortlake, Kew, Richmond, Twickenham, Teddington and Hampton.