Arnoldi is a surname. Notable people with the surname include:
Bartholomaeus Arnoldi (1465–1532), Augustinian friar associated with Martin Luther Charles Arnoldi (born 1946), American painter, sculptor and printmaker Per Arnoldi (born 1941), Danish designer and artist Vladimir Arnoldi (1871–1924), Russian children's writer and biologist Walter Edwin Arnoldi (1917–1995), American engineer
See also
Arnoldi iteration, an algorithm in algebra Paa arnoldi, a species of frog