A tailpiece is a component on many stringed musical instruments that anchors one end of the strings, usually the end opposite the end with the tuning mechanism the scroll, headstock, peghead, etc.

The tailpiece anchors the strings, so it must be strong enough to withstand their combined tension. Tailpieces of the violin family or viol families of instruments, including double basses, are attached by a "tailgut" looped around the end pin or end button. Originally made of animal gut and adjusted with difficulty by means of a knot, tailguts are now usually made of wire or nylon monofilament, and more easily adjusted with threaded collars, usually made of brass, on the ends.

Tailpieces are made of many materials. Violin tailpieces are typically of wood, usually ebony, rosewood, boxwood, or rarely pernambuco. Other materials include cast light metal, and composites including plastic. Choice of material may have more than just cosmetic effect; a well-made instrument is sensitive to tailpiece weight, mass distribution, and tailgut placement on the saddle. Fretted string instrument tailpieces are typically made of metal.