ZJ or zJ may refer to: Places Zhejiang, a province of China
Science and mathematics Zeptojoule (zJ), a small SI unit of energy Zettajoule (ZJ), a large SI unit of energy ZJ theorem, 1968, in group theory
Transport Jeep Grand Cherokee (ZJ), 1993 models of the sports utility vehicle Zambezi Airlines (2008–2012; IATA:ZJ)