GPS radio occultation (RO) measurements from a low-earth orbiting (LEO) satellite can determine profiles of atmospheric temperature in the troposphere and stratosphere with high vertical resolution. The RO technique can also provide electron density perturbations in the ionospheric E region. We discuss in this review the application of GPS occultation data for the studies of the dynamical structure of the troposphere, stratosphere and ionosphere. By analyzing RO data obtained by the GPS/MET (GPS/ Meteorology) experiment, the detailed thermal structure near the tropical tropopause has been described. The GPS/MET temperature data have also been used to determine the global distribution of atmospheric gravity wave energy in the stratosphere. These studies indicate enhanced wave activity over regions of tropical convection, in particular, around the Indonesian Archipelago. In addition, orographic generation of atmospheric waves is recognized over the Andean mountain range, whose effects reach the ionosphere, producing the sporadic E layers.