In January 2005, Šašić made her debut for Germany's senior national team against Australia. She scored her first goal in a friendly match against Canada in September 2006. A tibia fracture ruled her out for the 2007 FIFA Women's World Cup. She was part of Germany's squads claiming bronze at the 2008 Summer Olympics and winning the title at the 2009 European Championship, where she scored in the semi-final against Norway. At both tournaments, she was a reserve player with limited playing time. Šašić was called up for the German 2011 FIFA Women's World Cup squad. She was part of the victorious German team at UEFA Women's Euro 2013.