USS K-7 (SS-38) was a K-class submarine of the United States Navy. Her keel was laid down by the Union Iron Works at San Francisco, California, under a subcontract from Electric Boat Company of Groton, Connecticut. She was launched on 20 June 1914, sponsored by Mrs. Katie-Bel McGregor, daughter of the president of Union Iron Works, and commissioned at Mare Island on 1 December with Lieutenant J. V. Ogan in command.