Environmental concerns and cost reduction have encouraged the use of natural fillers as reinforcement in polymer composites. Currently, a wide variety of reinforcement, such as natural fibers and nanocellulose, are used for this purpose. Composite materials with natural fillers have not only met the environmental appeal, but also contribute to developing low-density materials with improved properties. The production of natural fillers is unlimited around the world, and many species are still to be discovered. Their processing is considered beneficial since the natural fillers do not cause corrosion or great wear of the equipment. For these reasons, polymer reinforced with natural fillers has been considered a good alternative for obtaining ecofriendly materials for several applications, including the automotive industry. This review explores the use of natural fillers (natural fibers, cellulose nanocrystals, and nanofibrillated cellulose) as reinforcement in polymer composites for the automotive industry.