This is a list of the tallest mountains in the Solar System. This list includes peaks on all celestial bodies where significant mountains have been detected. For some celestial bodies, different peaks are given across different types of measurement. The Solar System's tallest mountain is possibly the Olympus Mons on Mars with an altitude of 21.9 to 26 km. The central peak of Rheasilvia on the asteroid Vesta is also a candidate to be the tallest, with an estimated height between 19 and 22 km from peak to base.
Heights are given from base to peak (although a precise definition for mean base level is lacking). Peak elevations above sea level are only available on Earth, and possibly Titan. On other planets, peak elevations above an equipotential surface or a reference ellipsoid could be used if enough data is available for the calculation, but this is often not the case.
The following images are shown in order of decreasing base-to-peak height.