He started his international career on 12 October 1966 in Ankara versus Turkey. In his second match versus Albania he scored his first four of his 68 goals in the national team. He was member of the 1970 FIFA World Cup team. With ten goals he was the best scorer in this tournament. 1972 Germany won the European Championship and Müller was again the best scorer of this tournament. 1974 he won with Germany the FIFA World Cup where he scored the second goal in the 2:1 victory over the Netherlands. After this tournament he resigned from the team.