This paper describes the gamma‐ray burst detection capability of the gamma‐ray spectrometer on board the Mars Observer spacecraft. The instrument is designed to respond to significant bursts by suspending its observation of the martian surface in favor of optimizing the collection of pre‐burst, burst, and post‐burst data. The results are expected to contribute to our understanding of gamma‐ray bursts through a high‐energy resolution search for line emission, by the examination of spectral shapes and by comprising one leg of an arrival time network to determine the direction of origin.