Hain might refer to:
- Hain, Thuringia, a municipality in Thuringia, Germany.
- Hain (planet), a fictional planet in the Hainish or Ekumen novels of Ursula K. Le Guin
- Hain Celestial Group, a natural foods company
- Hain (river), a Belgian tributary of the Scheldt river
- Peter Hain, British politician
- Ludwig Hain, German bibliographer
- Repertorium bibliographicum, a reference book commonly abbreviated as "Hain"