Lutetia, (UK: loo-TEESH-ə, also US: ; Latin: [luːˈteːtia]; French: Lutèce [lytɛz]) also known as Lutetia Parisiorum ( pə-RIZ-i-OR-əm; Latin: [... pariːsiˈoːrʊ̃ː]; lit. 'Lutetia of the Parisii'), was a Gallo–Roman town and the predecessor of modern-day Paris. Traces of an earlier Neolithic settlement (c. 4500 BC) have been found nearby, and a larger settlement was established around the middle of the 3rd century BC by the Parisii, a Gallic tribe. The site was an important crossing point of the Seine, the intersection of land and water trade routes.

In the 1st century BC, the settlement was conquered by Romans and a city began to be built. Remains of the Roman forum, amphitheatre, aqueduct and baths can still be seen. In the 5th century it became the capital of the Merovingian dynasty of French kings, and thereafter was known as Paris.

Many artifacts from Lutetia have been recovered and are on display at the Musée Carnavalet.