There are 95 known moons of Jupiter, as of 1st November 2023. Jupiter has the largest number of moons of any planet in the Solar System.
The most massive of the moons are the four Galilean moons, which were independently discovered in 1610 by Galileo Galilei and Simon Marius. They were the first objects found to orbit a body that was neither Earth nor the Sun. The Galilean moons are by far the largest and most massive objects to orbit Jupiter. The other 91 known moons and the rings together make up just 0.003% of the total orbiting mass. The four are Io, Europa, Ganymede and Callisto. They are roughly the same size as Earth's moon, some are a bit bigger, some are smaller.
From the end of the 19th century, dozens of much smaller Jovian moons have been discovered. All these are less than in diameter, with most barely exceeding . Their orbital shapes range from nearly perfectly circular to highly eccentric and inclined. Many revolve in the direction opposite to Jupiter's spin (retrograde motion). Orbital periods range from seven hours (taking less time than Jupiter does to spin around its axis), to some three thousand times more (almost three Earth years).
List of moons
This list starts with those that go around Jupiter (orbit) the fastest. That is, they have the shortest orbital period. Moons highlighted in purple are the "Galilean moons," moons highlighted in dark gray have a retrograde orbit, and moons with the regular white background have a prograde orbit.