J15 may refer to:

Vehicles Aircraft Junkers J 15, a German experimental aircraft Shenyang J-15, a Chinese carrier-based jet fighter

Locomotives GSR Class J15, an Irish steam locomotive LNER Class J15, an English steam locomotive class

Ships , a Sandhayak-class survey ship of the Indian Navy

Other uses Bacterial pneumonia County Route J15 (California), a County route in Tulare County, California Elongated square bipyramid, a Johnson solid (J15) J15, a Nissan J engine model