Amalthea can refer to:
- Amalthea (mythology), the foster-mother of Zeus in Greek mythology.
- Amaltheia, alternative name of the Cumaean Sibyl
- Amalthea (cargo ship)
- Amalthea (moon), a moon of Jupiter.
- 113 Amalthea, an asteroid in the (main) asteroid belt.
- Amalthea, a ship bombed by the communist Anton Nilson in Malmö, Sweden in 1908.
- Lady Amalthea, a character in the fantasy novel and animated movie The Last Unicorn.