5O

5O or 5-O may refer to:


 * ASL Airlines France (IATA airline code: 5O)
 * 5-O-caffeoylquinic acid, see Chlorogenic acid
 * 5-O-(4-coumaroyl)-D-quinate 3'-monooxygenase
 * 5-O-Methylations
 * Cyanidin 3-O-rutinoside 5-O-glucosyltransferase
 * Anthocyanin 5-O-glucoside 6'''-O-malonyltransferase
 * a slang term for a Ford Mustang GT automobile with a 5.0 L engine
 * 5.0, 2010 album by Nelly