Jesse Bartlett "Oley" Oldendorf (16 February 1887 - 27 April 1974) was an admiral in the United States Navy, famous for defeating a Japanese force in the Battle of Leyte Gulf during World War II.

Graduating from the United States Naval Academy in 1909, he served on cruisers and destroyers before World War I, then after assignments on a freighter and a transport, was engineering officer on the USS Seattle, and executive officer of the transport Patricia. This was followed by onshore assignments and a stint as flag secretary of the Special Service Squadron.

Oldendorf's first command was the destroyer Decatur (DD-341), from 1922 to 1927. From 1939 to August 1941 he commanded the Houston, then joined the staff of the Naval War College.

Upon US entry into World War II, he was promoted to Rear Admiral and assigned to the Aruba-Curaçao sector of the Caribbean, then in August moved to the Trinidad sector, with anti-submarine warfare as his primary activity. From May to December 1943 he commanded Western Atlantic escorts from Argentia, Newfoundland.

Oldendorf shifted to the Pacific in January 1944, commanding Cruiser Division 4 from Louisville (CA-28), and supporting landings in the Marshalls, Palaus, Marianas, and Leyte.

On 24 October 1944 he deployed his force of battleships and cruisers in a classic battle line formation across the Surigao Strait southwest of Leyte, and defeated the Japanese Southern Force in the Battle of Surigao Strait, the last naval battle fought by surface ships alone.

He was promoted to Vice Admiral in December, commanded battleships in the landings at Lingayen, and was wounded during the Battle of Okinawa while on the Pennsylvania (BB-38).

After the war, Oldendorf commanded the 11th Naval District and the Western Sea Frontier, retiring in September 1948.

The destroyer USS Oldendorf (DD-972) was named in his honor.