John Sanford Barnes (May 12, 1836 – November 22, 1911) was a United States Navy officer and businessman and naval historian.

He entered the US Naval Academy at Annapolis, Maryland, at age 14, serving after his graduation aboard Preble, and under Commodore Stewart on San Jacinto in Europe and the West Indies, and on Saratoga.

From 1869 to 1880 he was in private business, largely engaged in obtaining financing for what was to become the Great Northern Railway.

He devoted time also to collecting memorabilia of the Navy during the American Revolution and War of 1812.

He served as the first President of the Naval History Society and edited the first volume of its publications, "The Log Books of the Serapis, Alliance, and Ariel," before his death in 1911.