Héctor Decio Rossetto (September 8, 1922 in Bahía Blanca, Argentina – January 23, 2009 in Buenos Aires) was one of the best chess players in Argentine history.
He earned the title of International Master in 1950 and the Grandmaster title in 1960.
He was a five-time Argentine Champion (1942, 1944, 1947, 1962, and 1972). Rossetto won the Mar del Plata chess tournament in 1949 and again in 1952 (shared with Julio Bolbochán). He also won in Mar del Plata (KIM) in 1962.
He was the director of the 1978 Chess Olympiad in Buenos Aires.
After Miguel Najdorf he was the most important Argentine chess player of his time.