According to Article 62 of the ICJ Statute, a third state can be granted permission to intervene before the Court provided ‘that it has an interest of a legal nature which may be affected by the decision in the case’. The interest of a legal nature is a crucial requirement under Article 62 and the scope of intervention largely depends on the definition of such a requirement. In light of the recent case law of the Court, the author explores the different types of legal interest that could justify permitting a third state to intervene before the ICJ.