Abstract This article analyses how investment tribunals apply attribution standards in their case practice. Attribution standards as applied by investment tribunals will be assessed in two different categories. First, the article will survey how tribunals apply traditional attribution tests, which originally refer to establishing internationally wrongful acts, as defined under Articles 4, 5 and 8 of ARSIWA. Second, the article will examine how attribution tests are applied and defined in so called non-traditional attribution scenarios, such as in the context of establishing the jurisdiction of arbitral tribunals, the applicability of the umbrella clause, certain declarations of the state (right of representation in the field of estoppel), as well as certain issues relevant to decide about the state’s involvement in private contracts in situations of corruption. The article ultimately presents a plea for nuanced application for attribution standards under different attribution scenarios instead of the automatic application of ARSIWA attribution standards.