P-42 or P42 may refer to:
Vessels , a corvette of the Argentine Navy , a submarine of the Royal Navy , a patrol vessel of the Irish Naval Service
Other uses Curtiss XP-42, an American experimental fighter aircraft GE P42, a diesel locomotive Lake City Air Force Station, a closed United States Air Force radar station in Tennessee MAPK1, p42 mitogen-activated protein kinase Papyrus 42, a biblical manuscript Phosphorus-42, an isotope of phosphorus P42, a Latvian state regional road P-42, a specially redesigned record-setting Sukhoi Su-27 Soviet fighter aircraft P42, three-dimensional space group number 77