Good question! Pluto has five known moons. Its first and largest moon Charon was discovered in 1978. Charon is roughly half the size of Pluto itself, so often Pluto and Charon are referred to as a double [dwarf] planet system. More recently in 2005, small moons Nix and Hydra were discovered by a Hubble Space Telescope team. Then in 2011, the moon Kerberos was discovered. This moon is even smaller than Nix and Hydra, and orbits in between those two moon orbits. Finally, the smallest moon Styx was discovered in 2012 by a team in charge of the New Horizons spacecraft. Styx has an orbit distance in between Charon’s and Nix’s orbits.

Pluto has five known moons: Charon, Nix, Hydra, Kerberos, and Styx. Here's a Hubble telescope photograph of the largest three:

Many large non-planetary objects actually have moons, including some asteroids.

Pluto has at least five moons, named Charon, Styx, Nix, Kerberos, and Hydra. Of these, Charon is the only good-sized one, about half of Pluto's already small diameter.