A Pet is a person who, by consent and within an agreed frame, takes on the role, behaviour or headspace of a companion animal. The Pet role can be assumed briefly within a scene, sustained over a long-term dynamic, or expressed ceremonially through gear, gestures and rituals. The species evoked, the intensity of the persona and the surrounding relationship structure vary widely.

The Pet role emerged as a distinct identity within BDSM and Leather communities as Petplay traditions developed their own vocabulary, gatherings and ceremonial practices during the late twentieth and early twenty-first centuries.

Different communities and dynamics place different weight on the Pet identity. Some treat it as a scene role assumed for particular occasions; others treat it as a lasting facet of identity within a chosen dynamic.