Chapter 4 delves into the powers of the EAEU in their substance. It addresses the concept common to all international organizations – attributed competences – and the way it is articulated in the EAEU. A number of areas fall under the exclusive competence of the organization, although the range of such powers is rather limited and there is no clear typology of competences. Specific attention is devoted to the doctrine of implied powers as a manifestation of the Court’s ability to interpret the distribution of powers and due to the attempt of the Member States to curtail this option in the EAEU. Given the fragmented nature of implied powers research and necessity to situate the EAEU in this respect, this chapter provides an overview of the adoption of this doctrine in distinct legal orders and offers a classification of approaches. This allows to demonstrate that the EAEU Treaty provisions, regardless the seeming wish of the drafters, do not in effect preclude the Court from establishing a balanced approach to implied powers. Therefore, it is enabled to exercise its authority to interpret competences in this respect and enhance legal order autonomy.