In this paper, the effect of biaxial strain on the mobility of single-layer transition metal dichalcogenides (MoS2, MoSe2, WS2 , and WSe2) is investigated by accounting for the scattering from intrinsic phonon modes, remote phonons, and charged impurities. Ab ini t io simulations are employed to study a strain-induced effect on the electronic bandstructure, and the linearized Boltzmann transport equation is used to evaluate the low-field mobility. The results indicate that tensile strain increases the mobility. In particular, a significant increase in the mobility of single-layer MoSe2 andWSe2 with a relatively small tensile strain is observed. Under a compressive strain, however, the mobility exhibits a nonmonotonic behavior. With a relatively small compressive strain, the mobility decreases and then it partially recovers with a further increase in the compressive strain.