Gemma is a recurring term in the Mana series. Individually, it can refer to:
- The seed of the Tree of Mana.
- The unseen character from Sword of Mana.
- Gemma Knights, the name given to swordsmen who protect the Tree of Mana in Adventures of Mana/Sword of Mana, possibly named after the character.
- The non-player character from Secret of Mana (called "Jema" in the Super NES version).
- In Children of Mana, certain gems have Gemma in their names as a reference.