Stone was selected to Canada's junior team for the 2012 World Junior Championships, held in Alberta. He began the tournament with a hat-trick and an assist in the first contest, an 8–1 win against Finland, and consequently was named Canada's player of the game. After losing their semi-final against Russia, Canada defeated Finland to win the bronze medal. Finishing the tournament with a team-leading seven goals and ten points, Stone was named one of Canada's three best players, as selected by the coaches.