This paper focuses on the specific attributes of the interpretation of international law from the theoretical perspective and through the analysis of selected case-law at the international, European and national level. The key document that sets forth the basic interpretation rules is the Vienna Convention on the Law of Treaties (VCLT); deemed to be the codification of customary law, the VCLT is steadfastly respected in essentially all countries of the world. However, in the international environment, the interpretation procedures incorporated in the Convention, primarily Article 31 et seq. of the VCLT, must be applied autonomously, i.e. separately from national interpretation or interpretation supplied by other authorities; autonomous interpretation only permits the latter as a subsequent instrument used for some measure of inspiration. In view of its importance and recognition in case-law, the concept of autonomous interpretation is a pivotal topic of this paper. Apart from the description itself of the functioning of the autonomous interpretation, the author also analyses several associated issues and challenges.