Hannen is a surname. Notable people with the surname include:
Hermione Hannen, British actress Isobel Hannen (née Torrance Jr.) (born 1962), Scottish curler and coach James Hannen (Baron Hannen), British judge Sir Nicholas John Hannen, British barrister, judge and diplomat Nicholas "Beau" Hannen, British actor Athene Seyler, married to Nicholas "Beau" Hannen, also went by the name Athene Hannen in her personal life