USS Margaret O (SP-614) was a civilian motorboat that temporarily served in the U.S. Navy during World War I.

Margaret O, a 55-foot motor pleasure boat, was built in 1915 at Neponset, Massachusetts, by George Lawley & Sons.

After being acquired by the Navy for World War I service she was placed in commission in October 1917 as USS Margaret O (SP-614).

She was assigned section patrol use, presumably in New England waters.

Post-war she was decommissioned and then returned to her owner in April 1919.