Spectral amplitude ratios of horizontal-to-vertical motion produced on seismographs of Apollo 12, 14, and 15 lunar impacts of meteoroids, the Apollo 14 and 15 lunar modules, and the Apollo 15 S4B, show consistent differences among the recording sites. On the assumption that the motion in the portions of the records chosen for analysis (near maximum amplitude) represents predominantly fundamental mode Rayleigh waves and that the compressional wave velocity structure is similar to that derived in other investigations involving the Apollo active and passive seismic experiments and in view of estimates of elastic properties of the surface derived from Surveyor spacecraft landings, estimates are made of the shear wave velocity structure under the three sites. Near-surface velocities are about 35 m/s at the three sites. The results for site 14 indicate an increase to about 100 m/s near 8-m depth and to 200 m/s at 38-m depth. Results for sites 12 and 15, although they differ in detail, show a smoother gradient and generally a greater velocity at a given depth than that indicated at site 14, reaching velocities of about 400 m/s near 120-m depth. If the assumed P velocity structures are correct and if changes in S velocity coincide with changes in P velocity, then Vp/Vs decreases from 2.9 to 2.0 in the upper 19 m at site 12, in the upper 38 m at site 14, and in the upper 21 m at site 15.