The use of natural plant fibers as reinforcing fillers in fiber-polymer composites has drawn much interest in recent years. Natural plant fibers as reinforcing fillers have several advantages over inorganic fillers such as glass fibers; they are abundant, readily available, renewable, inexpensive, biodegradable, of low density, and of high specific strength. Hemp fibers are one of the most attractive natural plant fibers for fiber-reinforced composites because of their exceptional specific stiffness. In this review, we summarize recent progress in developments of the hemp fiber reinforced composites such as hemp fiber reinforced unsaturated polyester (UPE), hemp fiber reinforced polypropylene (PP), hemp fiber reinforced epoxy composites, and so on, illustrate with examples how they work, and discuss their intrinsic fundamentals and optimization designs. We are expecting the review to pave the way for developing fiber-polymer composites with higher strength.