P56

P56 may refer to:


 * HMS Usurper (P56), a submarine of the Royal Navy
 * INS Sujata (P56), a patrol vessel of Indian Navy
 * Northrop XP-56 Black Bullet, an American prototype fighter aircraft
 * Papyrus 56, a biblical manuscript
 * Percival P.56 Provost, a British trainer aircraft
 * P56, a state regional road in Latvia