A worm drive is a gear arrangement in which a worm (which is a gear in the form of a screw) meshes with a worm wheel (which is similar in appearance to a spur gear). The two elements are also called the worm screw and worm gear. The terminology is often confused by imprecise use of the term worm gear to refer to the worm, the worm wheel, or the worm drive as a unit.

The worm drive or "endless screw" was invented by either Archytas of Tarentum, Apollonius of Perga, or Archimedes, the last one being the most probable author. The worm drive later appeared in the Indian subcontinent, for use in roller cotton gins, during the Delhi Sultanate in the thirteenth or fourteenth centuries.