Bertus "Bert" Sitters (born 10 December 1941) is a retired Dutch swimmer and swimming coach. He competed at the 1960 Rome Olympic Games in the 200m butterfly and at the 1964 Tokyo Olympics in the 100m freestyle and 4 × 200m freestyle relay.
After retiring from competition, in 1967–1972 and 1982–1986 he worked as a swimming and water polo coach in Spain. During 1972–1982 and 1986–1989 he trained the Dutch national team, preparing it for the 1976, 1980, 1984 and 1988 Olympics as well as world and European championships. Since 1989 he is a TV commentator of aquatic events with Eurosport.