James Robert Kalsu (April 13, 1945 – July 21, 1970) was an American football player who was an All-American tackle at the University of Oklahoma and an eighth-round selection in the 1968 NFL/AFL draft by the Buffalo Bills of the American Football League. Kalsu joined the U.S. Army as an officer after the 1968 season and was killed in action in the Vietnam War in 1970. Kalsu was one of two professional football players killed in the Vietnam War and the last to be killed serving as a soldier in a war until Pat Tillman in 2004.