Abstract We report the detection of a traveling ionospheric disturbance (TID) captured by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) Active Ionospheric Sounding (AIS) instrument aboard the Mars Express spacecraft at 150–250 km altitude. TID manifests as quasi‐periodic modulations in the ionosphere, and was observed by MARSIS‐AIS as deviations in electron density relative to background levels and undulations in the ionospheric altitude. The analysis suggests that this TID exhibited multi‐cycle wave train characteristics, corresponding to horizontal wavelengths of ∼200 km. Our investigation demonstrates that this TID is generated by the propagation of atmospheric gravity waves (GWs), which is confirmed by an ionospheric simulation for the conditions of the observations. This investigation not only marks the first tracking of Martian GWs using MARSIS but also allows us to investigate the two‐dimensional (2D) vertical propagation of these waves from the lower atmosphere to the ionosphere.