Tassin-la-Demi-Lune (French pronunciation: [tasɛ̃ la d(ə)milyn]) or simply Tassin is a commune in the Metropolis of Lyon in the Auvergne-Rhône-Alpes region, central-eastern France.

The town of Tassin-la-Demi-Lune is located in the western suburbs of Lyon and is part of Lyon Metropolis.

The city is connected by four train stations: Écully-la-Demi-Lune, Tassin, Alaï and Le Méridien.

Line 5 and 55 also connected the city to other metro stations.

Its inhabitants are named Tassilunois (masculine) and Tassilunoises (feminine) in French.