Harvey Curtiss Barnum Jr. (born July 21, 1940) is a former United States Marine Corps officer who received the Medal of Honor during the Vietnam War. He was the fourth Marine to receive the medal for actions in Vietnam. He retired from the Marine Corps in 1989 after more than 27 years of service. Barnum served as Deputy Assistant Secretary of the Navy for Reserve Affairs from July 23, 2001 to January 20, 2009. He also served as Acting Assistant Secretary of the Navy (Manpower and Reserve Affairs) from January 21 to April 30, 2009.