Vermehren is a surname. Notable people with the surname include:
Erich Vermehren (1919–2005), German anti-Nazi Isa Vermehren (1918–2009), German religious sister Frederik Vermehren (1823–1910), Danish painter Johann Bernhard Vermehren (1777–1803), German poet Knud Vermehren (1890–1985), Danish gymnast Ruth Vermehren (1894–1983), Danish Lutheran priest