Klas Fleming may refer to:
Klaus Fleming (Clas Eriksson Fleming 1535–1597), Finnish-Swedish admiral (c. 1550–1616), Swedish soldier and historian (1649–1685), Governor of Örebro (1680–1681) Claes Adolph Fleming (1771–1831), Swedish count and member of the Swedish Academy Clas Larsson Fleming (1592–1644), admiral and administrator of the Royal Swedish Navy HSwMS Clas Fleming, a Swedish Navy mine cruiser
See also Fleming of Louhisaari, about the family