Campbell has represented the Republic of Ireland at U-17, U-19 and senior level.
In 2010, together with Ciara Grant , Dora Gorman, Denise O'Sullivan, Siobhán Killeen and  Clare Shine, she was a member of the Republic of Ireland U-17 squad that were runners-up in the 2010 UEFA Women's Under-17 Championship and quarter-finalists in the 2010 FIFA U-17 Women's World Cup.
In the UEFA championship, Campbell scored twice: the winner in 2–1 group victory against Sweden and  the semi-final goal in the 1–0 win over Germany.
In the World Cup, Campbell scored the opening goal in a 3–0 win against Ghana.

Campbell played for a senior Republic of Ireland team of home-based players in a behind closed doors match against Northern Ireland.
She then won her first official cap in a friendly against Switzerland at Richmond Park in August 2011.
Campbell came on as substitute for Louise Quinn after 62 minutes during the 1–0 defeat by the Swiss.
On 5 April 2014 in a 2015 FIFA Women's World Cup qualifier against Germany at Tallaght Stadium, Campbell provided two assists with throw-ins.
Despite Campbell's effort the Republic of Ireland lost 3–2.
Campbell has represented the Republic of Ireland at U-17, U-19 and senior level. In 2010, together with Ciara Grant , Dora Gorman, Denise O'Sullivan, Siobhán Killeen and  Clare Shine, she was a member of the Republic of Ireland U-17 squad that were runners-up in the 2010 UEFA Women's Under-17 Championship and quarter-finalists in the 2010 FIFA U-17 Women's World Cup. In the UEFA championship, Campbell scored twice: the winner in 2–1 group victory against Sweden and  the semi-final goal in the 1–0 win over Germany. In the World Cup, Campbell scored the opening goal in a 3–0 win against Ghana.
Campbell played for a senior Republic of Ireland team of home-based players in a behind closed doors match against Northern Ireland. She then won her first official cap in a friendly against Switzerland at Richmond Park in August 2011. Campbell came on as substitute for Louise Quinn after 62 minutes during the 1–0 defeat by the Swiss. On 5 April 2014 in a 2015 FIFA Women's World Cup qualifier against Germany at Tallaght Stadium, Campbell provided two assists with throw-ins. Despite Campbell's effort the Republic of Ireland lost 3–2.
Megan Campbell