A fundamental understanding of the mechanical properties and the failure mechanism of hybrid fiber-reinforced polymers (FRP) is required for the effective application of FRP in construction. This paper presents a new methodology for predicting the tensile behavior of hybrid FRP tendons by considering the interfacial stress transfer between the resin and the fibers in hybrid FRP. Subsequently, the authors utilize the fundamental concepts of fracture mechanics to derive a model capable of predicting the mechanical properties of hybrid FRPs. For this paper, the authors conducted an experimental study on the tensile properties of hybrid basalt/carbon FRP tendons and hybrid glass/carbon FRP tendons. They identified the effects of resin type, fiber fraction, and fiber arrangement over the cross section. The results show that the stress-strain relationship of hybrid FRP can be modified from the linear behavior of FRP to a ductile behavior with a steady pseudoyielding plateau and a high ultimate failure strain. Meanwhile, the load drop in hybrid FRP, which is attributable to the fracture of the fibers with low elongation capacity, can be controlled effectively by the proper design of the hybrid fiber proportions, resin type, and volume fraction. The proposed hybridization results in improving the deformation ability of fibers with low elongation capacity. Moreover, the proposed model for the description of failure progression and prediction of mechanical properties is verified by good agreement with the experimental results of this paper and those from prior studies by others.