Alex Crosby (11 January 1945 – 2 February 1968) was a US Marine Corps sergeant during the Vietnam War. Crosby was in charge of calling in air support for the Marines as they struggled during the Battle of Hue, and MACV-SOG operative Alex Mason later took his radio and called in helicopter attacks on NVA strongpoints. Crosby joined the assault on foot, only to be killed at a nearby doorway.