Mechanical components in automobiles are exposed to high stresses, temperature, and corrosive environments. Automakers often attempt to create the lightest cars possible to increase vehicle speed and power. The aim of producing a light car is to increase vehicle performance and efficiency as well as safety and comfort. Vehicle weight is an important factor that directly affects energy consumption, for example, a 10% reduction in weight provides a 7% fuel economy. Over the past few decades, the use of high-performance polymers and various blends of these polymers in automobile components has shown an increasing trend. Polymers are used in automobile components due to their light weight and relatively better mechanical properties. Polymeric materials provide more freedom in vehicle design and reduce vehicle weight. In this chapter, the most commonly used polymers in automobiles and various mixtures of these polymers are described. Information about automobile interior and exterior components and under-hood components manufactured using polymer mixtures is given.