"Arthur" refers to many characters in the Sonic the Hedgehog franchise. Arthur may also refer to:
- King Arthur, the main antagonist for the first half of Sonic and the Black Knight
- King Arfur, a character in the Adventures of Sonic the Hedgehog television series
- Arthur, a character in the Sonic the Comic series published by Fleetway
- Arthur Mongoose, father of Mina Mongoose in the Sonic the Hedgehog comic series and its spin-off comic series published by Archie Comics