USS Passumpsic (AO-107), the only United States Navy ship to bear the name, was an Ashtabula-class fleet replenishment oiler that served in the U.S. Navy from 1946 to 1973, then transferred to the Military Sealift Command to continue service as United States Naval Ship USNS Passumpsic (T-AO-107). She was the only U.S. Navy ship to bear the name Passumpsic, after the Passumpsic River in Vermont.

USS Passumpsic (AO-107) was laid down on 8 March 1945 as Maritime Commission Hull 2703 by Sun Shipbuilding and Drydock Company, Chester, Pennsylvania. She was launched on 31 October 1945, sponsored by Mrs. M. F. Draemel, wife of Rear Admiral Milo F. Draemel, then Commandant of the 4th Naval District, and commissioned on 1 April 1946. Due to her beginning as a "Maritime" Hull, Passumpsic has the distinction of being one of only six naval ships to have her Frame numbers running from Aft - Forward, instead of Forward to Aft.

After a shakedown in the Caribbean Sea, Passumpsic operated out of Long Beach, California, under the control of Commander, Service Force Pacific, servicing U.S. Pacific Fleet units while attached to Service Squadron 1 and Service Squadron 3. She visited Japan, Taiwan, Korea, Southeast Asia, Hong Kong, North Borneo, the Fiji Islands, Australia, Arabia, Ceylon, the Philippines, Midway Atoll, Oahu, the Marshall Islands, and the Mariana Islands.

From June 1950 through February 1954, Passumpsic spent 34 of 44 months outside the United States. Though not subjected to hostile fire during the Korean War, Passumpsic received nine battlestars for her Korean War service.

Passumpsic’s assignments after the Korean War entailed annual deployments to the Western Pacific.

Upon return from deployment in April 1964, Passumpsic underwent an INSURV Board inspection at Long Beach Naval Shipyard in preparation for "Jumboization," a project of modernization and renovation for Mispillion-class fleet oilers. She steamed on 12 October 1964 for the American Shipbuilding Company yard at Lorain, Ohio, where the conversion was to take place. At Boston Naval Shipyard a Supply Overhaul Assistance Program (SOAP) was set up to sort, identify, and repackage the ship's stock of repair parts and to receive, sort, and stow the repair parts supplied by the contractor and the U.S. Navy in conjunction with the conversion programs. After passage through the Panama Canal and St. Lawrence Seaway, Passumpsic was placed "in commission, in reserve" on 26 November 1964 and most of her crew detached, leaving a nucleus party of four officers and 28 enlisted men under the command of Lcdr. James. K. Beates. The ship was then turned over to the American Shipbuilding Company.

The conversion involved transferring her existing midships superstructure to a newly constructed tank section. The original hull was cut and the bow and stern sections were added to the new tank section. Conversion modifications increased Passumpsic's length by 91 feet (28 m), her light displacement from 7,423 tons to 12,840 tons, her full-load displacement from 25,500 to 34,350 tons, and her maximum draft from 32 feet (9.8 m) to 36 feet (11 m).

Passumpsic departed Lorain on 22 November 1965 with a merchant marine master and civilian crew. She arrived at the Boston Army Base piers, South Boston, Massachusetts, on 1 December 1965.