The 5th constituency of the Ain is a French legislative constituency in the Ain département.

It was created by ordinance n°2009-935 of 29 July 2009, ratified by the French Parliament on 21 January 2010.

It consists of the cantons of Ambérieu-en-Bugey, Brénod, Champagne-in-Valromey, Hauteville-Lompnes, Izernore, Lhuis, Nantua, North Oyonnax, Oyonnax South, Poncin, Saint-Rambert-en-Bugey, Virieu-le-Grand.

The constituency was first contested in the 2012 legislative elections.