Rear-Admiral Sir Thomas Louis, 1st Baronet (bap. 11 May 1758 – 17 May 1807) was an officer of the British Royal Navy who served in three wars and saw numerous actions, notably as one of Horatio Nelson's "Band of Brothers" in the Mediterranean in 1798 who commanded ships at the Battle of the Nile. Louis had previously seen extensive action during the American Revolutionary War and later was to be second in command at the Battle of San Domingo, for which service he was made a baronet.