Montparnasse (French: [mɔ̃paʁnas] (listen)) is an area in the south of Paris, France, on the left bank of the river Seine, centred at the crossroads of the Boulevard du Montparnasse and the Rue de Rennes, between the Rue de Rennes and boulevard Raspail. It is split between the 6th, 14th, and 15th arrondissements of the city. Montparnasse has been part of Paris since 1669.

The area also gives its name to:

• Gare Montparnasse: trains to Brittany, TGV to Rennes, Tours, Bordeaux, Le Mans; rebuilt as a modern TGV station;
• The large Montparnasse – Bienvenüe métro station;
• Cimetière du Montparnasse: the Montparnasse Cemetery, where, among other celebrities, Charles Baudelaire, Constantin Brâncuși, Jean-Paul Sartre, Simone de Beauvoir, Man Ray, Samuel Beckett, Serge Gainsbourg and Susan Sontag are buried;
• Tour Montparnasse, a lone skyscraper.

Students in the 17th century who came to recite poetry in the hilly neighbourhood nicknamed it after "Mount Parnassus", home to the nine Muses of arts and sciences in Greek mythology. The hill was levelled to construct the Boulevard Montparnasse in the 18th century. During the French Revolution many dance halls and cabarets opened their doors, becoming gathering points for artists. The area is also known for cafés and bars, such as the Breton restaurants specialising in crêpes (thin pancakes) located a few blocks from the Gare Montparnasse. The Pasteur Institute is located in the area. Beneath the ground are tunnels of the Catacombs of Paris.