Harmenszoon or Harmensz. is a Dutch surname. Notable people with the surname include:
Harmensz.
Jan Harmensz. Muller (1571–1628), Dutch engraver and painter
Harmenszoon
Jacob Harmenszoon (1560–1609), Dutch theologian Jan Harmenszoon Krul (1601–1646), Dutch playwright Rembrandt (Rembrandt Harmenszoon van Rijnn; 1606–1669), Dutch painter and printmaker