London—Middlesex (also known as Middlesex East riding) was a federal electoral district that was represented in the Canadian House of Commons from 1979 to 1997. It was located in the province of Ontario.

Middlesex East riding was created in 1976 from parts of Huron—Middlesex, London East and Middlesex—London—Lambton ridings. It initially consisted of the Townships of Biddulph, London, North Dorchester, Westminster and West Nossouri (excluding the Village of Belmont) and the southeast part of the City of London.