Five ships of the United States Navy have borne the name USS Louisiana in honor of the 18th state.

• USS Louisiana (1812) was a sloop that served in the War of 1812
• USS Louisiana (1861) was a propeller-driven steamer that served in the American Civil War
• USS Louisiana (BB-19) was a Connecticut-class battleship commissioned 2 June 1906 and decommissioned 20 October 1920
• USS Louisiana (BB-71) was a Montana-class battleship cancelled before her keel was laid down
• USS Louisiana (SSBN-743) is an Ohio-class submarine currently in active service
• CSS Louisiana was commissioned by the Confederate States of America during the American Civil War
• USRC Louisiana (1819) was a wood hull topsail schooner that served in the United States Revenue Cutter Service from 1819 to 1824