A mobile (UK: , US: ) is a type of kinetic sculpture constructed to take advantage of the principle of equilibrium. It consists of a number of rods, from which weighted objects or further rods hang. The objects hanging from the rods balance each other, so that the rods remain more or less horizontal. Each rod hangs from only one string, which gives it the freedom to rotate about the string. An ensemble of these balanced parts hang freely in space, by design without coming into contact with each other.

Mobiles are popular in the nursery, where they hang over cribs to give infants entertainment and visual stimulation. Mobiles have inspired many composers, including Morton Feldman and Earle Brown who were inspired by Alexander Calder's mobiles to create mobile-like indeterminate pieces. John Cage wrote the music for the short film Works of Calder that focused on Calder's mobiles. Frank Zappa stated that his compositions employ a principle of balance similar to Calder mobiles.