The Opel Senator is a full-size executive car (E-segment) produced by the German automaker Opel, two generations of which were sold in Europe from 1978 until 1993. A saloon, its first incarnation was also available with a fastback coupé body as the Opel Monza and Vauxhall Royale Coupé.

Through the international divisions of General Motors, it was also known in various markets as the Chevrolet Senator, Daewoo Imperial (in South Korea), Vauxhall Royale (until 1983) and Vauxhall Senator (which took the place of the Royale on Vauxhall models when the Opel brand was phased out from 1983). It was also sold as the Opel Kikinda in Yugoslavia, where it was produced under licence by IDA-Opel in Kikinda, Serbia, after which it was named.

The original Senator shared its platform with the smaller Opel Rekord, the latter being lengthened to make the Senator. The second generation of that car, from 1987, shared its base with the Rekord's Opel Omega successor, which was again lengthened to produce the Senator.