J12 may refer to:

Vehicles Aircraft Nanchang J-12, a prototype Chinese fighter

Automobiles Hispano-Suiza J12, a French luxury car Subaru J12, a Japanese hatchback

Ships , a Visby-class destroyer of the Swedish Navy

Other uses Chanel J12, a Swiss-made watch County Route J12 (California) Triangular bipyramid, a Johnson solid (J12) Marlboro Pike Line, a bus route in the Washington Metro Area Viral pneumonia