Chonan may refer to:
- Chōnan, the Japanese moniker for the eldest son in a family.
- Chōnan, Chiba, a town in Japan
- Cheonan, a city in South Korea
- Battle of Chonan, a battle in the city during the Korean War
- ROKS Cheonan (PCC-772) A South Korean corvette sunk on March 26, 2010.
- Chonan Gang, the Korean stage name of Tsuyoshi Kusanagi, a Japanese actor/singer
- Ryo Chonan (born 1976), Japanese mixed martial artist