Recently, the instrumented sleeper has been developed to measure the sleeper response in-situ. An analytical model of the dynamics of railway sleepers has been developed to calculate rapidly the sleeper response under vertical wheel loads. However, lateral wheel loads are not taken into account in this model but would influence the sleeper response. This paper presents a new analytical model of the dynamics of railway sleepers under lateral wheel loads. In this model, the sleeper is considered as a Euler-Bernoulli's beam resting on a visco-elastic foundation. Thereafter, by combining the relation between the reaction forces and displacements of the periodically supported beam, the sleeper response can be calculated with help of the Green's function. Finally, the numerical application shows the influence of the laterals wheel load on the sleeper response.