P39

P39 or P-39 may refer to:


 * HMS P39, a United Kingdom Royal Navy submarine which saw service during the Second World War
 * P-39 Airacobra, an American fighter aircraft of World War II
 * Papyrus 39, a manuscript of the Gospel of John
 * Phosphorus 39, one of the isotopes of phosphorus
 * Fos-binding protein p39