A car rental or car hire agency is a company that rents automobiles for short periods of time (ranging from a few hours to a few weeks) for a fee. It is an elaborate form of a rental shop, organized in numerous local branches, primarily located near airports or busy city areas and often complemented by a website allowing online reservations. There are also third party websites (such as online travel agencies) which compare quotes from the major car rental agencies.

Car rental agencies primarily serve people who have a car that is temporarily out of reach or out of service, for example travellers who are out of town or owners of damaged or destroyed vehicles who are awaiting repair or insurance compensation. Because of the variety of sizes of their vehicles, car rental agencies may also serve the self-moving industry needs, by renting vans or trucks, and in certain markets other types of vehicles such as motorcycles or scooters may also be offered.

Alongside the basic rental of a vehicle, car rental agencies typically also offer extra products such as insurance, global positioning satellite (GPS) navigation systems, entertainment systems, and even such things as mobile phones.