On 28 May 2012, Zieler was named the third goalkeeper of the German squad for the 2012 European Championship, remaining as back-up as they reached the semi-finals. On 15 August 2012, he started in net in a friendly match against Argentina and was sent off, becoming the first German goalkeeper to earn a red card since the founding of the German national team. He was sent off after half an hour for conceding a penalty with a foul on José Sosa, but replacement Marc-André ter Stegen saved the penalty from Lionel Messi.