It is well known that changes in material properties across an interface will produce differences in the behavior of reflected and transmitted waves. On larger spatial scales, this mesoscopic behavior can result in the roughening of an initially planar shock front after interacting with grains of different orientations. We have developed an analytical model for treating stress wave scattering at grain boundaries based on crystal plasticity. Using this technique we can predict the anisotropic elastic-plastic velocity surfaces and grain boundary scattering configuration for crystalline materials undergoing deformation by slip. Following a brief description of the model we describe laser-induced shock experiments where we have measured the surface roughening due to shock-microstructure interactions. Spatial scales of the surface roughening were observed to scale approximately with the grain size of the material, which in this case was polycrystalline Be and Cu-doped Be.