J3, J03, J 3 or J-3 may refer to:
Aircraft and airlines Junkers J 3, a German experimental fighter aircraft J-class blimp, a class of US Navy airships Ishikawajima-Harima J3, a Japanese turbojet aircraft engine Piper J-3 Cub, a light aircraft Northwestern Air, a Canadian airline, IATA code J3
Roads and vehicles County Route J3 (California), in the United States Kempas Highway and Jalan Datin Halimah, Johor State Route J3 in Malaysia JAC J3, a subcompact car
Ships and submarines J3, a design type of Junsen type submarine of the Imperial Japanese Navy , later , a J-class submarine J3 battlecruiser, a design study for the Royal Navy's 1921 Fleet modernization programme
Other uses J3, the main perturbing force to be counteracted in order to have a frozen orbit in orbital mechanics Janko group J3, in mathematics J3 League, in the Japan Professional Football League LNER Class J3, a class of British steam locomotives Nikon 1 J3, a camera J3, the operations branch of joint military staff Samsung Galaxy J3 (2016), a smartphone Samsung Galaxy J3 Pro Triangular cupola, Johnson Solid number 3
See also 3J (disambiguation)