'''PIW''' may refer to:
* Public Interest Watch, a US group that claims to fight charitable trust abuse * Pikwitonei Airport, the IATA code for the airport in Canada * PIW or Państwowy Instytut Wydawniczy (''State Publishing Institute''), Polish publishing house founded in 1946 * pounds per inch width, an imperial measure * Person in water, a term used by water rescue teams in the case of a Man overboard. {{disambig}}