John Elphinstone, also known as John Elphinston (1722 – 28 February 1785), was a senior British naval officer who worked closely with the Russian Navy after 1770, with approval from the Admiralty, during the period of naval reform under Russian Empress Catherine II. Together with the Scottish-born Samuel Greig, or Samuil Karlovich Greig (Самуил Карлович Грейг), as he was known in Russia, and Admiral Sir Charles Knowles, Elphinstone was a member of the naval staff, headed by Count Alexei Grigoryevich Orlov, which, though it lacked naval experience, was able to defeat the Turkish fleet at the Battle of Chesma Bay, near Chios Island, off the far western coast of Turkey.