Thorin can refer to:
- Thorin, name of three Dwarvish Kings in J. R. R. Tolkien's writings:
- Thorin I, the first king at Ered Mithrin
- Thorin II Oakenshield, a companion of Bilbo Baggins in The Hobbit
- Thorin III Stonehelm, King of Erebor in the Fourth Age
- Thorin (chemistry), an organic arsenic compound used in the determination of thorium and barium
- Olof Thorin, Swedish mathematician