| Birth Date: | 4 March 1961 |
René Nico Hubertus Klaassen (born March 4, 1961, in Velp) is a former field hockey defender from the Netherlands, who participated in two Summer Olympics: in Los Angeles (1984) and in Seoul (1988).
He ended up in sixth place in California with the Dutch National Men's Team, and won the bronze medal in South Korea four years later, after defeating Australia (2-1) in the Bronze Medal Game. Klaassen earned a total number of 126 caps, scoring three goals, in the years 1984–1990. He was also on the side that won the world title in Lahore, Pakistan. After that tournament he retired from international competition.