24 Themis is a C-type asteroid with a diameter of 220 kilometers, discovered in 1853 by A. de Gasparis. It orbits in the main body of the asteroid family that bears its name (see Themis family); semimajor axis 3.13 astronomical units (AU), perihelion 2.71 AU, aphelion 3.55 AU, inclination 0.8 rcsecond. In 2008 and 2009, two teams of scientists independently announced the discovery of water-ice on the surface of Themis, lending credence to the idea that colliding asteroids (as well as comets) delivered large quantities of water to Earth in the remote past.

Themis is also a satellite of Saturn reported by William Pickering in 1898 to be in orbit between Titan and Hyperion, but subsequently not seen again.