Agnus (Latin for lamb) can be used to refer to:
- Agnus (beetle), a stag beetle genus
- Agnus Dei (Latin: "Lamb of God"), referring to Jesus Christ
- Agnus scythicus, Latin for Vegetable Lamb of Tartary, a mythologic lamb-plant
- MOS Technology Agnus, an integrated circuit in the OCS chipset of the Commodore Amiga computer
- Vitex agnus-castus, a Mediterranean plant