KJ or kJ is an acronym that could be referring to:

• K. J. Yesudas, A famous musician/singer from Kerala, India
• KJ is the model code of the Jeep Liberty
• kilojoule (kJ), an SI unit of energy equal to 10³ joules
• Khairy Jamaluddin, Malaysian politician
• British Mediterranean Airways IATA airline designator
• Kevin Johnson nickname, former NBA player
• Kym Johnson, a ballroom dancer
• Karaoke jockey, a disc jockey that specializes in running karaoke events
• Kay-Jay Harris, American football player
• K. J. Hippensteel, American tennis player
• Kiryas Joel, New York
• Kohtla-Järve, Estonia
• Keila-Joa, Estonia
• KJHK
• Kodomo no Jikan, a manga
• KJ-52, Christian rapper.
• Katherine Jenkins.

de:KJ eo:Kj fr:KJ ko:KJ id:KJ it:KJ ja:KJ nn:KJ ksh:KJ (Watt ?ßß datt?) fi:Kj