USS Mary Louise (SP-356) was a patrol boat that served in the United States Navy from August to October 1917.

History
United States
Name	USS Mary Louise
Namesake	Previous name retained
Builder	Milton Point Shipyard, New York
Acquired	24 August 1917
In service	27 August 1917
Fate	Returned to owner 30 October 1917
General characteristics
Type	Patrol vessel
Length	47 ft 10 in (14.58 m)
Beam	9 ft 6 in (2.90 m)
Draft	4 ft (1.2 m)
Speed	8 knots

Mary Louise was built as a private boat of the same name in by the Milton Point Shipyard in New York. On 24 August 1917, the U.S. Navy acquired her on a free-lease basis from her owner, J. S. Williams of Wilmington, North Carolina, for use as a patrol boat during World War I. She was placed in service as USS Mary Louise (SP-356) on 27 August 1917.

Assigned to the 6th Naval District, Mary Louise served on section patrol duties for about two months.

Mary Louise was returned to her owner on 30 October 1917.