Arentz is a surname. Notable people with the surname include:
Bjarne Arentz (1928–2017), Norwegian alpine skier Charles Arentz (1878–1968), Norwegian sailor Dick Arentz (born 1935), American fine art photographer and author Frederik Arentz (1702–1779), Norwegian Lutheran bishop Hans Severin Arentz (1806–1875), Norwegian politician Samuel S. Arentz (1879–1934), American politician Steven J. Arentz (born 1951), American politician