PX or px may refer to:
- Praxair (stock symbol)
- Air Niugini (IATA airline code)
- Index of the Prague Stock Exchange ( PX Index)
- Post exchange, a store operated by the Army and Air Force Exchange Service on US Army posts
- Pedro Ximénez, a grape used in the making of sweet sherries and wines from Montilla-Moriles
- Part exchange
- p-Xylene (Paraxylene), an aromatic hydrocarbon, based on benzene with two methyl substituents, of which PX is the industrial symbol.
- Chi Rho, an early christogram formed by superimposing the first two letters in the Greek spelling of the word Christ in such a way to produce the monogram ☧
- Medical prescription, the symbol "℞" looks like "Px".
- Medical procedure, a non-surgical medical intervention, such as a blood transfusion or superficial biopsy.
- Operation PX, a planned Japanese biological attack on the United States in World War II.