The Lotus 51 was an open-wheel Formula Ford race car built in 1967 by the British motorsport team Lotus. It was powered by a Ford Crossflow four-cylinder engine (the same type of engine used in the Ford Cortina), developing a respectable , which drove the rear wheels through either a Renault R-8 type 330 4-speed, or a Hewland 5-speed manual transmission.
The Lotus 51 became a bestseller for Colin Chapman and the Lotus team in 1967. 218 vehicles were built and sold (some sources speak of only 150 vehicles). The price for one vehicle was ã955.
The car was derived from, and based on, the Lotus 31, a Formula 3 car from Lotus. The racing car was agile and fast, had a short wheelbase, and was extremely light with a curb weight of . In 1969 the car was replaced by the Lotus 61. In 1968 the 51R - a one-off - was built. The car had wider sidepods and was originally intended as a concept for a successor. The car was sold for ã1095 to a US collector who never entered the 51R in racing competitions.