Newcomen may refer to:
People John Newcomen (c.1613–1630), English first white settler murdered by another white settler in Plymouth Colony, Massachusetts Matthew Newcomen (c. 1610–1669), English nonconformist churchman Thomas Newcomen (1663–1729), English ironmonger and inventor
Other uses Viscount Newcomen, of Mosstown in the County of Longford, a title in the Peerage of Ireland Newcomen baronets, of Kenagh in the County of Longford, a title in the Baronetage of Ireland Newcomen Society, a British learned society Newcomen Society of the United States, an educational foundation Newcomen atmospheric engine, a device to harness the power of steam to produce mechanical work