HP1 or variant, may refer to:Heterochromatin Protein 1, an important marker molecule in epigenetic research The postal code for part of Hemel Hempstead in Dacorum, see HP postcode area hP1, a Pearson symbol Harry Potter and the Philosopher's Stone, the first novel in J.K. Rowling's Harry Potter series Harry Potter and the Philosopher's Stone (film), the first film in J.K. Rowling's Harry Potter series Handley Page Type A aka H.P.1, an airplane HP-1, a glider designed by Richard Schreder HP1, a type of photographic stock, see Ilford HP Haemophilus phage HP1, a virus Hp.1 (proceed), from German railway signalling