Fourteen active dust devils were observed by the High Resolution Stereo Camera (HRSC) on Mars Express, which enable the first analysis of the forward speed of dust devils on Mars determined from orbit. Results show speeds on the order of 20 m/s, which compares favorably with values of the wind profiles estimated from the Martian Climate Database for higher altitudes. Smaller dust devils of 1 km height and very small diameters were found moving only at 1.5 to 6.0 m/s in agreement with surface wind speeds.