Several types of changes can take place between the conclusion of a treaty and when its provisions call for interpretation, e.g. changes in the political, social, historical or legal context; technological changes; linguistic changes; or changes in the law. Traditionally, interpreters refused to consider changes that may have occurred since the treaty's conclusion. Today, many argue that it is more legitimate for a treaty interpreter to take account of these changes and use an ‘evolutionary' or ‘dynamic' interpretation. The issue of changes is particularly relevant in the context of the World Trade Organization (WTO) Treaty, because it combines long-standing provisions with more recent ones, and because international trade has evolved greatly, notably with electronic trade (e-commerce) and new means of distribution that did not exist when the WTO was concluded. The different types of changes discussed in this article may be grouped into four non-mutually exclusive types of situations, which will be examined through the prism of the interpretation process set out in Articles 31-33 of the Vienna Convention on the Law of Treaties (VCLT). While different types of evolutionary interpretations can be considered under standard rules of interpretation in public international law, the use of the term ‘evolutionary interpretation' allows for a more global understanding of the phenomenon, and might have, at the very least, a symbolic value.