Lambton—Kent—Middlesex is a provincial electoral district in southwestern Ontario, Canada. It elects one member to the Legislative Assembly of Ontario. It was created in 1999 from parts of Lambton, Chatham—Kent and Middlesex when ridings were redistributed to match their federal counterparts. In 2007, the riding was redistributed, and it lost Plympton-Wyoming, Enniskillen, Petrolia and Oil Springs while it gained the rest of North Middlesex, Lucan Biddulph and Middlesex Centre.