Île-de-France Mobilités (French: [il də fʁɑ̃s mɔbilite]; IDFM) is a governmental authority (EPA) that controls and coordinates the different public transport companies operating in Paris and the rest of Île-de-France. In this capacity, it issues operating contracts for the various services, owns the buses and rolling stock used on those services, and acts as the main financing body for transport projects in the region. It coordinates the operation of RATP Group, SNCF, and the nearly 90 Optile-affiliated bus companies.
The origins of the organization can be traced back to the Syndicat des Transports Parisiens (STP), which was created by the French Government in 1959 to coordinate the various operations in the Paris region. The STP also provided oversight for the construction of the Réseau Express Régional and established the unified Carte orange fare payment system. In 1991, the STP was empowered to cover the entire Île-de-France region.