USS L-6 (SS-45) was an L-class submarine of the United States Navy. Her keel was laid down on 27 May 1914 by Craig Shipbuilding Company in Long Beach, California. The L-boats designed by Lake Torpedo Boat (L-5 through L-8) were built to slightly different specifications from the other L-boats, which were designed by Electric Boat, and are sometimes considered a separate L-5 class. L-6 was launched on 31 August 1916 sponsored by Mrs. William R. Monroe, and commissioned on 7 December 1917 with Lieutenant H. B. Berry in command.