The Opel Kadett C is a small family car which was produced by the German automobile manufacturer Opel from 1973 to 1979. The Kadett C, which was the third generation of the Opel Kadett, was released in August 1973, and was Opel's version of the General Motors' "T-Car". It was the last small Opel to feature rear-wheel drive, and remained in production at Opel's Bochum plant until July 1979, by which time Opel had produced 1,701,076. Of these, 52% had been exported outside West Germany, most of them to markets in other parts of western Europe. In other world markets however, various badge engineered versions of the Kadett C remained in production as late as the mid 1990s under other GM brand names.

Despite being out of mainstream production since 1979, in Europe the Kadett C retains something of a cult following (along with its Vauxhall Chevette sister) largely due to its popularity in the sport of drifting where its conventional rear wheel drive layout is valued, and its ability to be easily upgraded with engines from larger Opel cars.