Montmagny-L'Islet (French pronunciation: [mɔ̃maɲi lilɛ]) is a former provincial electoral district in the Chaudière-Appalaches region of Quebec, Canada that elected members to the National Assembly of Quebec.

As of its final election, it included the cities or municipalities of Montmagny, Saint-Jean-Port-Joli, L'Islet, Sainte-Perpétue, Saint-Pamphile and Cap-Saint-Ignace.

It disappeared in the 2012 election and the successor electoral district was Côte-du-Sud.

[3] Its territory never changed during its entire existence, despite overall electoral map reforms in 1980, 1985, 1988, 1992 and 2001.

[4] * Increase is from UFP 2Johnson is split between Centre-du-Québec and MontérégieSee also: