La Défense (French: [la de.fɑ̃s]) is a major business district just west of the city limits of Paris. It is part of the Paris Metropolitan Area in the Île-de-France region, located in the department Hauts-de-Seine spread across the commune of Courbevoie, as well as parts of Puteaux and Nanterre.

La Défense is Europe's largest purpose-built business district with 560 hectares (1,400 acres) of area, 72 glass and steel buildings (of which 19 are completed skyscrapers), 180,000 daily workers, and 3,500,000 square metres (38,000,000 sq ft) of office space. Around its Grande Arche and esplanade ("le Parvis"), La Défense contains many of the Paris urban area's tallest high-rises.

The district is located at the westernmost extremity of the 10-kilometre-long (6.2 mi) Historical Axis of Paris, which starts at the Louvre in Central Paris and continues along the Champs-Élysées, well beyond the Arc de Triomphe along the Avenue de la Grande Armée before culminating at La Défense. The district is centred in an orbital motorway straddling the Hauts-de-Seine département municipalities of Courbevoie, Nanterre, and Puteaux. La Défense is primarily a business district and hosts a population of 25,000 permanent residents and 45,000 students. La Défense is also visited by 8,000,000 tourists each year and houses an open-air museum.