Аннотация:In this work we investigate the influence of the material’s internal characteristic length parameters on the dispersion relations for the surface shear waves in the piezoelectric materials. We derive semi-analytical solution for the dynamic anti-plane problem of the second gradient electroelasticity taking into account the elastic, electric field and inertia gradient effects. We found that in opposite to the known solutions of the second gradient elasticity, in the presented coupled field theory we can obtain a solution for the second (‘‘optical’’) branch of the dispersion relations. However, this solution should be abandoned since it has non-decaying behavior with purely imaginary attenuation coefficient. Also it is shown that gradient piezoelectric modulus that defines the high order piezoelectric effect, i.e. the coupling between the strain gradients and the electric field gradients, can be insignificant in the assessments on the spatial dispersion effects for the electroacoustic surface waves.