This list includes peaks on all celestial bodies where significant mountains have been detected.
The solar system's tallest mountain is possibly the Olympus Mons on Mars with an altitude of 21.9 to 26 km.
Peak elevations above sea level are only available on Earth, and possibly Titan.
[1] 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.