The Mercedes-Benz W123 is a range of executive cars produced by German manufacturer Mercedes-Benz from November 1975 to January 1986. The W123 models surpassed their predecessor, the Mercedes-Benz W114, as the most successful Mercedes, selling 2.7 million units before production ended in the autumn of 1985 for the saloon/sedan versions and January 1986 for coupés and estates/station wagons.

The Mercedes-Benz W114 and W115 are the internal designations Mercedes-Benz used for a generation of front-engine, rear-drive, five-passenger sedans and coupés introduced in 1968, with three-box styling by Paul Bracq — succeeding the W110 models introduced in 1961; and manufactured until model year 1976, when the W123 was released.