A free reed aerophone is a musical instrument that produces sound as air flows past a vibrating reed in a frame. Air pressure is typically generated by breath or with a bellows. In the Hornbostel–Sachs system, it is number: 412.13. Free reed instruments are contrasted with non-free or enclosed reed instruments, where the timbre is fully or partially dependent on the shape of the instrument body, Hornbostel–Sachs number: 42.

A reed is a thin strip of material that vibrates to produce a sound on a musical instrument. Most woodwind instrument reeds are made from Arundo donax or synthetic material. Tuned reeds are made of metal or synthetics. Musical instruments are classified according to the type and number of reeds.