Duchene made his international debut at the 2008 World U-17 Hockey Challenge. He scored ten points in six games to help Team Ontario to a gold medal. The same year, he was named to Canada's under-18 team for the 2008 IIHF World U18 Championships in April and was selected as captain at the 2008 Ivan Hlinka Memorial Tournament in August; he won gold at both tournaments. Playing in his second major junior season, Duchene participated in Canada's junior camp ahead of the 2009 World Junior Championships, but was ultimately cut from the team's final roster.