An experimental investigation was carried out to evaluate the fatigue performance of two different glass fiber reinforced polymer (GFRP) dowel systems. The diameter and spacing of the first GFRP dowel system was based on the current design standard for steel dowels and consisted of 1.5-inch diameter GFRP dowels spaced at 12 inches on center. The second GFRP dowel system, which consisted of 1.5-inch diameter GFRP dowels spaced at 6 inches on center, was determined to be equivalent in load transfer capacity to that of the steel dowel system currently recommended for 12-inch thick concrete highway pavements. Each dowel system was installed in a full-scale laboratory pavement slab and subject to fatigue loading. Each pavement slab constructed and tested was 6 feet wide by 12 feet long by 12 inches thick and contained an 1/8-inch transverse joint at midlength. Fatigue loading consisted of 5 million cycles of a 9,000-pound wheel load. A simulated subgrade consisting of six simply supported steel beams was used to support the slabs during testing. Based on the results of this research along with the results from the research of others, a preliminary design guideline for the incorporation of GFRP dowels within contraction joints of concrete highway pavements was developed.