Hossein Nassim (born 27 April 1952) is an Iranian swimmer.
He who was a member of Iran national water polo teams participating in the 1976 Summer Olympics and 1970, 1974, and 1986 Asian Games, and won a gold medal in 1974.
Nassim was known for his national records in the backstroke, and his contribution to the Iran men's national water polo team from the early 1970s through the late 1980s.
Nassim immigrated to Germany in 1987, and is now a coach and instructor with swim clubs there.