The fatigue behavior of adhesively-bonded glass fiber-reinforced polymer (GFRP) joints is affected by the loading sequence. Analysis of several experimental data for composite materials and adhesively-bonded composite joints showed that the loading sequence effect is a function of the loading type, the applied loading levels and the material under investigation. Exhibited failure modes, related to the loading pattern, significantly affect the development of damage in adhesively-bonded composite joints. The aim of this chapter is to investigate the load sequence effect of both block and variable amplitude loading conditions on the fatigue behavior of adhesively-bonded pultruded GFRP joints.