This article examines the relationship between the law of State responsibility and WTO law, by focusing on three important, still rather unexplored, areas: acts and actors; circumstances precluding wrongfulness of an act; and cessation of a wrongful act. In certain respects, it is easy to see that WTO law contains special rules, replacing the general rules, or that there are no special provisions regulating State responsibility issues. However, one of the main arguments in this article is that, when examining the above relationship, it is more relevant to talk about ‘border areas’, than ‘borders’. In many cases, it will not be possible to draw clear borders be-tween general and special rules. For example, State responsibility rules can be applied directly in WTO dispute settlement, or used as tools for interpreting WTO provisions. But it can of-ten be complicated to determine whether there is a gap, calling for direct application, or if there is a special provision, which needs to be interpreted. To a large extent, the relationship be-tween the two regulatory frameworks is instead characterized by mutualism, where the under-standing of a certain concept in one framework can contribute to the understanding of the same concept in the other.