In his second year of major junior, Möller represented Sweden at the 2008 World Junior Championships in the Czech Republic. He contributed 5 points in 6 games as Team Canada defeated Sweden in the gold medal game 3–2 in overtime. The following year, Möller was lent to Sweden's under-20 team by the Los Angeles Kings to compete in his second World Junior Championships in Ottawa. He was chosen as team captain for Sweden but was kept from a second gold medal game against Team Canada due to a fractured clavicle, suffered against Russia during the tournament. Despite not playing in the final, he earned another silver medal as Sweden was defeated 5–1.