Harlon Henry Block (November 6, 1924 – March 1, 1945) was a United States Marine who was killed in action on Iwo Jima during World War II. Born in Yorktown, Texas, Block joined the Marine Corps with seven high school classmates in February 1943, and subsequently participated in combat on Bougainville and Iwo Jima. He is best known as one of the six servicemen photographed raising the American flag on Mount Suribachi, on February 23, 1945.