Composites have been the most widely used applications for coir fibers. One of the simplest approaches for manufacturing coir fibers based composites is to use the fibers as reinforcement and epoxy or other synthetic polymers as resins. Completely biodegradable coir-based composites have also been developed using natural polymers such as wheat gluten, soy-based resins, and synthetic biopolymers such as poly(lactic acid) as matrix. In addition, coir fibers have been physically and chemically modified and various fillers have been used to improve the properties of coir-based composites. Similarly, coir fibers have been combined with other fibers and matrices to develop hybrid composites with distinct properties suitable for various applications. This chapter covers the coir-based synthetic polymer composites, coir-based natural polymer matrix completely biodegradable composites, and also coir based hybrid composites in separate sections.