Over the years, civil engineering has faced several changes that have pushed it to seek significant developments, with the use of more efficient or innovative materials for specific applications. For concrete structures, the use of fiber-reinforced polymer (FRP) rebars as a substitute for steel reinforcements has become widespread in recent years, given the fact that FRP composites are not susceptible to corrosion. Consequently, several studies have explored the behaviour of FRP-reinforced concrete elements, both from the experimental and the numerical point of view. In this research, an extensive literature review is conducted and data collection is performed about flexural tests carried out on concrete elements, i.e., beams and slabs, reinforced with FRP rebars. The results of 140 tests are analyzed with the objective of studying the tension stiffening effect to characterize the behavior at the serviceability limit state. A classification of the main types of rebars is provided, mainly considering the characteristics which may influence the bond-slip behavior. Then, with reference to deflection control, a recalibration of the coefficients of the formulation reported in Eurocode 2 is proposed through a regression method. The outcomes of the research may support an update of existing Guidelines for the design and verification of FRP-reinforced concrete elements.