Dag Otto Lauritzen (born 12 September 1956) is a retired Norwegian professional cyclist. At the 1984 Summer Olympics in Los Angeles he won a bronze medal in the individual road race. He was the first Norwegian to win a stage of the Tour de France, which he did on Bastille Day in 1987 at Luz Ardiden. Over his career he rode the Tour de France eight times.
Lauritzen won the Norwegian National Road Race Championship in 1984 and the Norwegian National Time Trial Championship in 1990.
He is now a cycling commentator on Norwegian TV station TV 2.