Teräväinen has represented Finland on several youth levels, most notably in the World Junior Championships. In the 2013 tournament, he scored 11 points, placing fourth in the tournament scoring. In the following year, he was named the captain of the team, leading Finland all the way to the final. In the final, Finland defeated Sweden 3–2 in overtime. Teräväinen assisted all three of Finland's goals and was the overall scoring leader of the tournament.