Joseph K. Barnes was an American physician and the 12th Surgeon General of the United States Army (1864–1882).

The Surgeon General of the United States Army is the senior-most officer of the U.S. Army Medical Department (AMEDD). By policy, the Surgeon General (TSG) serves as Commanding General, U.S. Army Medical Command (MEDCOM) as well as head of the AMEDD. The surgeon general's office and staff are known as the Office of the Surgeon General (OTSG) and are located in Falls Church, Virginia.