Newcomen may refer to:
- Viscount Newcomen, an extinct viscountcy
People with the surname Newcomen:
- John Newcomen (circa 1613-1630), first white settler murdered by another white settler in Plymouth Colony, Massachusetts
- Matthew Newcomen (circa 1610-1669), English nonconformist churchman
- Thomas Newcomen (1663-1729), ironmonger and inventor of the steam engine