Novel fiberglass-reinforced composites were fabricated by the ultraviolet and visible (solar) irradiation of epoxidized vegetable oils in the presence of onium salt cationic photoinitiators. A variety of layup techniques and experimental conditions were explored to optimize composite fabrication. It was demonstrated that composites prepared by wet layup techniques containing up to five plies of glass cloth could be cured by a direct, 25-min exposure to solar irradiation. A series of composite samples were prepared using mixtures of epoxidized vegetable oils and synthetic epoxy resins, and their mechanical properties were evaluated. Based on these measurements, it may be concluded that photochemical routes to the fabrication of composites derived from epoxidized vegetable oils provide a simple, direct, and inexpensive route to the fabrication of composites with many potential low-performance applications.