Geosynthetics have been extensively used to fulfill many functions in multiple roadway applications. Geotextiles (woven and non-woven), geogrids (biaxial and multiaxial), and geocells are among the several geosynthetic products that have been successfully adopted to fulfill the functions of separation, filtration, reinforcement, stiffening, infiltration barrier, and drainage. Geosynthetics have been used in roadway applications such as mitigation of reflective cracking in structural asphalt overlays, stabilization of unbound aggregate layers, reduction of layer intermixing, reduction of moisture in structural layers, stabilization of soft subgrades, and mitigation of distress induced by shrink/swell subgrades. This presentation provides a framework to categorize the multiple objectives, functions, and mechanisms involved in the different roadway applications. It also highlights the significant benefits to roadway performance that can be brought with the use of geosynthetics in their design.