Vésteinn Hafsteinsson (born 12 December 1960 in Selfoss) is a retired discus thrower from Iceland, who represented his native country at four consecutive Summer Olympics, starting in 1984. At the Los Angeles summer Olympic Games he tested positive for nandralone and was disqualified. His personal best is 67.64 metres, thrown on May 31, 1989 in Selfoss. Hafsteinsson competed in five consecutive World Championships, starting in 1983, but never reached the final. He previously coached World and Olympic champion Gerd Kanter and is currently coaching Daniel Ståhl.