Crustal structure under continents and oceans as revealed by the most recent Rayleigh and Love wave dispersion data is described. These surface-wave determinations are concordant with the principal results from seismic-refraction measurements. Since surface-wave studies lead to average properties of the crust across areas of continental or oceanic dimensions they provide valuable supplementary data to the point-by-point refraction measurements. Regions inaccessible for refraction experiments may be explored by surface-wave methods. The velocity of shear waves in the upper silicic crust of continents deduced from study of the phase Lg is used in the interpretation of surface-wave data.