HP1

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