Sir William Mitchell, KCB (c. 1745 – 7 March 1816) was an officer of the British Royal Navy during the eighteenth and early nineteenth centuries. Mitchell is best known for rising from humble origins to high rank, having joined the Navy in 1766 as an able seaman and died in 1816 as a vice-admiral. His service was highly varied, including a circumnavigation of the world, command of a ship at the Battle of Camperdown in 1797 and a period as Sir James Saumarez's flag captain. He was also rumoured to have once been flogged round the fleet for desertion, although no firm evidence of this has been discovered.