Together with Tony Kane, Michael O'Connor and Marc Wilson, Gibson is one of several Northern Irish footballers, involved in an on going dispute between the Irish Football Association and the Football Association of Ireland over international eligibility. The dispute emerged after the Good Friday Agreement allowed people born in Northern Ireland to claim either Republic of Ireland and/or United Kingdom nationality. As a result, Gibson has been selected to represent both Northern Ireland and the Republic of Ireland at international level.
Northern IrelandGibson initially represented Northern Ireland at Under-16 level and was included in Victory Shield squads. However, he was dropped from the team after attending trials with Manchester United and subsequently switched allegiance to the Republic of Ireland. Before Gibson made his senior international debut for the Republic of Ireland, Nigel Worthington, the Northern Ireland manager, tried in vain to persuade him to switch his allegiances back.
Republic of IrelandGibson first represented the Republic of Ireland at under-17 level. Then during the 2005-06 season he captained both the Republic of Ireland under-19 and under-21 squads . On 14 November 2006, he also played for Republic of Ireland B in a 0-0 draw against Scotland B. In 2007, Gibson was included in several senior Republic of Ireland squads for Euro 2008 qualifiers, before he eventually made his debut in a 4-0 win against Denmark. During the away friendly, he came on as half-time substitute, replacing Andy Reid. In the 54th minute, Gibson fired a shot from outside the penalty area that the Danish keeper, Jesper Christiansen, could only palm away, allowing Shane Long to follow up and score the Republic's third goal. Gibson won his second full cap on 8 September 2007 in an away game against Slovakia. The Euro 2008 qualifier, which finished as a 2-2 draw, saw him again used as substitute, this time replacing Aiden McGeady after 61 minutes.