Rate coefficients for the N+NO→N2+O reaction are calculated over the temperature range 100--1000 K by a quasiclassical trajectory calculation on the 3A″ potential energy surface (PES) based on the semiempirical London-Eyring-Polanyi-Sato (LEPS) formalism, neglecting spin-orbit coupling. The calculated results are only slightly temperature dependent and are in excellent agreement with available experimental data and the JPL recommended rate coefficient [DeMore et al., 1994> at room temperature. The present results do not support either the rate coefficient arrived at by Siskind and Rusch [1992> from modeling of the terrestrial thermosphere or the one arrived at by Fox [1994> from modeling of the Martian thermosphere. Possible causes of the discrepancies between the calculated rate coefficients and those arrived at from modeling studies may be additional NO production (loss or loss and production) mechanisms in the Martian (terrestrial) thermosphere. ¿ American Geophysical Union 1996