Football Club Lorient Bretagne Sud (French pronunciation: [lɔʁjɑ̃ bʁətaɲ syd];), commonly referred to as FC Lorient (Breton: An Oriant), is a French professional association football club based in Lorient, Brittany. The club was founded in 1926 and currently competes in Ligue 2, having been relegated from Ligue 1 at the end of the 2023–24 season. Lorient plays its home matches at the Stade Yves Allainmat, named after the former mayor of Lorient. The stadium is surnamed Stade du Moustoir because of its location within the city. The team is managed by Olivier Pantaloni.

Lorient had a relatively bleak history nationally before 1998 when the club made its first appearance in Ligue 1 in the 1998–99 season. Before that, Lorient spent most of its life as an amateur club. Lorient's achieved its biggest honour in 2002 when the club won the Coupe de France defeating Bastia 1–0 in the final. Lorient has never won Ligue 1, but has won the Championnat National earning this honour in 1995. Regionally, the club has won five Brittany Division d'Honneur titles and six Coupe de Bretagne.

Lorient has most notably served as a springboard club for several present-day internationals such as Laurent Koscielny, André-Pierre Gignac, Michaël Ciani, Kevin Gameiro, Karim Ziani, Bakari Koné, Matteo Guendouzi, and Seydou Keita. French international Yoann Gourcuff, the son of Christian Gourcuff, began his career at the club before moving to Derby Breton rivals Rennes.