The Renault 18 is a large family car produced by French manufacturer Renault between 1978 and 1989, with South American production continuing until 1994. It formed the basis for the closely related Renault Fuego Coupé, with which it shared its floorpan and drivetrain, but with the Fuego initially using the negative offset type front suspension from the larger Renault 20/30, which became standardized across the 18 range from the 1983 model year onwards.

The D-segment is the 4th category of the European segments for passenger cars, and is described as "large cars".