Right to Strike under ILO Convention No. 87 (I.C.J.)

Abstract On May 21, 2026, the International Court of Justice (ICJ) rendered an advisory opinion on whether the right to strike is protected under the ILO Freedom of Association and Protection of the Right to Organise Convention, 1948 (Convention No. 87), following a decade-long controversy within the ILO’s tripartite constituency. Applying the customary rules of treaty interpretation contained in Articles 31 and 32 of the Vienna Convention on the Law of Treaties, the Court held that the right to strike is protected under Convention No. 87 as an integral part of freedom of association. It found that strike action falls within the ordinary meaning of the right of workers’ organizations to organize their “activities,” a conclusion confirmed by supplementary means of interpretation, including ILO supervisory practice, international human rights instruments and jurisprudence of regional courts. Two aspects of the advisory opinion are particularly significant. First, the Court adopted a flexible approach to the principle of systemic integration under Article 31(3)(c) of the Vienna Convention. Second, it recognized that the pronouncements of the ILO supervisory bodies may carry significant interpretative weight within their respective mandates. The advisory opinion thus contributes to the development of treaty interpretation while restoring legal certainty concerning the right to strike and clarifying an important aspect of the ILO supervisory system.