Baron Clas Eriksson Fleming (Finnish: Klaus Fleming) (1535, Pargas, Sweden – 13 April 1597, Pohja, Finland) was a Finnish-born member of the Swedish nobility and admiral, who played an important role in Finnish and Swedish history during the rise of Sweden as a Great Power. He was a trustee of Swedish kings John III and Sigismund Vasa. In 1569 Fleming became a member of the Privy Council, in 1571 he was made Lord High Admiral and in 1590 Lord High Constable.