Green composites have been produced from natural oils and agricultural co-products or residues. A variety of natural oil-based resins, both free radically- and cationically-cured, and agricultural filler/fiber reinforcements have been utilized in their production. The natural oils and agricultural filler/fibers of interest include tung, corn, soybean, fish, and linseed oils and spent germ, corn stover, wheat straw, and switchgrass. The structure, water absorption, and thermal and mechanical properties of the composites has been studied using Soxhlet extraction, thermogravimetric and dynamic mechanical analysis and tensile testing. These novel composites contain anywhere from 60 to 95% renewable materials and have properties suitable for nonstructural applications, such as automotive panels, wall panels, ceiling tiles, window frames, furniture and doors, in the automotive, construction and furniture industries.