Leif Carlson (born August 19, 1973) is a Canadian former international rugby union player.
A 6 ft 7 in forward, Carlson was a member of the Canada national team in 2002 and 2003. He was capped three times, including a match against Wales at Millennium Stadium. In 2003, Carlson made the 31-man preliminary squad for the Rugby World Cup and was the last player to be cut from the list after Al Charron declared fit.
Carlson played for Delta-based club Brit Lions and had a stint in England with Coventry.