Abstract FRP composite materials have exhibited outstanding potential in civil infrastructure applications to date due to the fact that they are lightweight, easy to install, and offer high strength-to-weight ratio. FRP composites have been used to construct more durable new infrastructure systems and strengthen existing structures. However, there are still concerns about the long-term durability performance of these materials when subjected to different environmental conditions. This chapter reviews the applications of FRP in civil infrastructures and their durability performance under different environmental conditions. Because it is important to predict the long-term durability of FRP composite under these conditions, several analytical models have been proposed. Some of them are summarized here, including predicting hygrothermal degradation of composite and bond strength at elevated temperatures.