Jo, jo, JO, or J.O. might refer to:
Arts and entertainment
Businesses and organizations
- Jo (given name)
- Jō (surname), a Japanese surname
- Cho (Korean name), a common Korean surname which can be romanized as "Jo"
- jō (杖), a wooden staff used in a few Japanese martial arts, about four Japanese feet long
- jō (丈), a Japanese unit of length equivalent to the Chinese zhang, equal to ten Japanese feet
- jō (畳), a Japanese unit of area corresponding to the area of a standard tatami mat (1×½ ken or 18 square Japanese feet)
- JO, U.S. Navy rating abbreviation for "journalist"
- Jordan (ISO country code)
- .jo, the internet country code top-level domain (ccTLD) for the country of Jordan
- Journal Officiel de la République Française, the official gazette of the Government of France