Nitric oxide decomposition has been studied in a shock tube, time-of-flight mass spectrometer system at 2700 to 4700 K and 1.5 to 3.5 atrn using neon as diluent. The overall decomposition rate was found to be second order in NO concentration and in good agreement with previously reported rates. N" 0" and O-atoms were the only observed reaction products. The concentration-time profiles of the observed species lend support to a mechanism of primary NO decomposition to N, and 0, with slower decomposition to N,O and O-atoms. A mathematical simulation of the reaction consisting of eight elementary reactions was deduced by fitting experimental data to simulated concentration-time profiles.