USS Tortuga (LSD-26) was a Casa Grande-class dock landing ship in the United States Navy. She was the first Navy ship to be named for the Dry Tortugas, a group of desert coral islets 60 miles west of Key West, Florida, which were discovered in 1513 by Spanish explorer Ponce de Leon.

The Casa Grande class was a class of dock landing ships used by the Royal Navy and the United States Navy during the Second World War. Nineteen ships were planned, but two, USS Fort Snelling and USS Point Defiance were cancelled before being completed.