SS Mission San Luis Rey was a Type T2-SE-A2 tanker built for the United States Maritime Commission during World War II.

After the war she was acquired by the United States Navy as USS Mission San Luis Rey (AO-128).

Later the tanker transferred to the Military Sea Transportation Service as USNS Mission San Luis Rey (T-AO-128).

Mission San Luis Rey was laid down 15 October 1943 under a United States Maritime Commission contract by Marine Ship Corporation, Sausalito, California; launched 29 January 1944; sponsored by Mrs. T. L. Phillips; and delivered 31 March 1944.

Chartered to Pacific Tankers, Inc. for operations, she spent the remainder of the War carrying fuel to Allied bases overseas (during which time she was awarded the National Defense Service Medal).