The K-car platform was a key automotive design platform introduced by Chrysler Corporation for the 1981 model year, featuring a transverse engine, front-wheel drive, independent front and semi-independent rear suspension configuration—a stark departure from the company's previous reliance on solid axle, rear-drive unibody configurations during the 1970s. Derived from Chrysler's L-cars, the Plymouth Horizon and Dodge Omni, the platform was developed just as the company faltered in the market, at first underpinning a modest range of compact/mid-size sedans and wagons—and eventually underpinning nearly fifty different models, including all-wheel drive variants—and playing a vital role in the company's subsequent resurgence.

A car platform is a shared set of common design, engineering, and production efforts, as well as major components, over a number of outwardly distinct models and even types of cars, often from different, but somewhat related, marques. It is practiced in the automotive industry to reduce the costs associated with the development of products by basing those products on a smaller number of platforms. This further allows companies to create distinct models from a design perspective on similar underpinnings. A car platform is not to be confused with a platform chassis, although such a chassis can be part of an automobile's design platform, as noted below.