Chapman is a former England U–18 captain. She made her senior international debut aged 17 years in May 2000 in a 2001 UEFA Women's Championship qualification match against Switzerland. The following month, she made her first start against Norway. In March 2002 she netted her first senior international goal in a 4–1 2003 FIFA Women's World Cup qualification win in the Netherlands. In her first spell with the national team, Chapman represented England at four major international tournaments; UEFA Euro 2001, UEFA Euro 2005, 2007 FIFA World Cup and UEFA Euro 2009. A two-time winner of the FA International Player of the Year in 2002 and 2010, Chapman took a break from the national team in March 2011 with a total of 82 caps and eight goals. She was recalled to the England squad in February 2014 by new manager Mark Sampson and helped them finish third at the 2015 FIFA World Cup.