Lilly has participated in the 1991, 1995, 1999, 2003, and 2007 editions of the FIFA Women's World Cup. She is a two-time World Cup champion, winning in 1991 and 1999; during extra time of the '99 Final against China, Lilly, standing on the goal line, blocked a Chinese shot which had passed goalkeeper Briana Scurry - since the tournament took place with the golden goal rule in effect, the game would have been over if China had scored - and in the ensuing shootout, she scored the goal which would give the US the lead. When she played against North Korea on September 11, 2007, in the 2007 FIFA Women's World Cup, she became the first woman (and only the third player overall) to participate in five different World Cup Finals; by scoring a goal against England on September 22, 2007, she became the oldest woman to score in the World Cup.