in Tibetan Buddhism, a mechanical device the use of which is equivalent to the recitation of a mantra (sacred syllable or verse). The prayer wheel consists of a hollow metal cylinder, often beautifully embossed, mounted on a rod handle and containing a tightly wound scroll printed with a mantra. Each turning of the wheel by hand is equivalent in efficacy to the prayer's oral recitation multiplied by the number of times the mantra is printed on the scroll.

Variants to the hand-held prayer wheel are large cylinders that can be attached to windmills or waterwheels and thus kept in continuous motion. The mantra on a prayer flag is similarly activated by the blowing of the wind.