William Gwin (6 December 1832 – 3 January 1863) was an officer in the United States Navy who was killed in action during the American Civil War.

During the next five years he was assigned to the sloop of war Germantown, flagship of the African Squadron, the steamer Princeton and the brig Bainbridge.

[2] Returning to the United States in mid-1861, Lieutenant Gwin began Civil War combat service in the newly acquired cruiser Cambridge and, later in the year, was assigned to the brig Perry.

Fire support from two of his gunboats, Tyler and Lexington, helped save Union troops from disaster in the Battle of Shiloh, bringing high praise from General Ulysses S. Grant.

[1] In reporting his death to the Navy Department, Gwin's squadron commander, Rear Admiral David Dixon Porter, remarked: "The country has lost one of its bravest officers.