Archenemy is someone's main enemy.

The term may also refer to:

• Arch Enemy, Swedish death metal band
• Archenemy Record Company
• ArchEnemies, comics
• Archenemy (Magic: The Gathering)
• ArchEnemy, a 2009 science-fiction and fantasy novel by Frank Beddor in his The Looking Glass Wars trilogy
• Archenemy (film), an American-British action film