This article focuses on the role and contribution of the International Court of Justice to developing and interpreting the right of peoples to self-determination. The most relevant cases decided by the Court so far, and briefly noted here, broadly fall within the decolonization context, save for the ongoing advisory proceedings in the Kosovo case. This simple taxonomy is based on a wide separation of the Court's case law in two main categories, namely decolonization and secession. The analysis of the place of secession under current international law serves to put into perspective the inquiry into whether any of the main principles applicable to the decolonization process, as elaborated by the Court, continue to be valid in the case of secession of a part of a state from an existing independent state. The article ends with a number of concluding remarks on the contribution of the Court to clarifying the right of peoples to self-determination as part of the corpus of international human rights law.