Ph2

ph2, ph-2, ph.2 or variant, may refer to:
 * AMD Phenom II CPU chip
 * PH2 (Planet Hunters 2), star system with a planet
 * PH2 b, a planet around that star
 * 1991 PH2 or 9341 Gracekelly
 * 1992 PH2 or (13089) 1992 PH2
 * Hall PH-2, biplane flying boat
 * Pander PH.2 Mayer, see List of aircraft (P)
 * biphenyl, Ph2 or Ph-Ph
 * Phenolphthalein, ph2 or phph
 * PH2, a postcode in Perth, Scotland, see PH postcode area
 * PH2− the phosphanide ion in inorganic chemistry
 * -PH2 the phosphanyl group in organic chemistry