Articles 62 and 63 of the Statute of the International Court of Justice address the prospect of third States intervening in contentious cases before the Court. The thesis presents an historical overview of these provisions, and explores conceptual tensions in their practice. First, it assesses questions concerning the consensual nature of the Court's jurisdiction, specifically its characterizations of inherent powers and procedural autonomy. In so doing, it also considers to what extent these characterizations may be constructively applied by arbitral tribunals. Second, it assesses questions concerning consistency in the interpretation of Article 62's "interest of a legal nature" and "may be affected by the decision" clauses. In so doing, it also considers to what extent these interpretations find support in the interpretation of similar terms by other institutions. The thesis concludes by observing how the Court might resolve these tensions doctrinally, without expressly departing from its existing body of practice.