The Eurasian Economic Union (hereinafter ‘EAEU’) is a new international organization established in the post-Soviet space. It is based upon past regional integration initiatives, but also claims to follow best European Union (hereinafter ‘EU’) practices. One of the clearest indications thereof in the legal field is the abundance of references to the case law of the Court of Justice of the European Union, which can be found in the rulings of the EAEU Court. The dissertation explores the legal nature and functioning of the EAEU by taking the theoretical framework of legal order autonomy, which is largely associated with the EU and the case law of its Court of Justice. Therefore, the aim is to find out whether the EAEU can be qualified as an autonomous legal order. This research has developed a number of indicia of internal and external legal order autonomy, which, in the absence of a definition of the latter, has proven to be a useful tool to unpack the complex legal system and functioning of the EAEU. Whereas the indicia are manifestations of legal order autonomy, there are certain essential preconditions, which must be met first, i.e. the existence of a legal order and international legal personality. Chapter 1 further identifies the following indicia of legal order autonomy: self-referential character of law; supranational judicial mechanisms (a mechanism ensuring uniform application and interpretation of law in all member states and a mechanism ensuring exclusive jurisdiction); supranational effect of legal norms (direct effect and primacy); interpretation of distribution of powers; and institutional supranationality. The next chapter sets out the historical background, evolution, and context of Eurasian integration, including the legal nature of the EAEU and the entities it has been built upon. Four relevant stages of Eurasian integration have been identified in Chapter 2. It is demonstrated that although there were many failures along the way, Belarus, Kazakhstan and Russia managed to create a rather viable core capable of pushing integration forward and eventually formalize it in the EAEU Treaty. Chapter 3 explores the functioning of the EAEU in terms of its institutional structure and decision-making, with a particular focus on the Eurasian Economic Commission as the main regulatory body of an alleged supranational character. This research challenges this idea of supranationality by uncovering the predominantly intergovernmental mode of operation not only of the EAEU as such, but also of the Commission. The chapter also focuses on the structure of the Court as the major institution on which legal order autonomy depends. It was demonstrated that the history of its establishment and the rules regarding its formation raise the question of judicial independence. Thereafter, this research focuses on the powers of the EAEU. Similarly to the EU, the principle of conferral is the basis of the EAEU’s functioning, and a number of areas fall under its exclusive competence. However, 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 distribution powers and the attempt of the Member States to curtail this option on the basis of the EAEU Treaty. Chapter 4 demonstrates that the EAEU Treaty provisions do not in effect preclude the Court from finding a balanced approach to the implied powers. Therefore, it is enabled to exercise its authority to interpret competences in this respect and enhance legal order autonomy. In Chapter 5, the EAEU legal system is further explored. It is found that the EAEU Treaty established its own legal order and its sources under the heading of ‘Union Law’. However, the hierarchy of rules and even the legal force of some of the acts is not always clear. Further, a problematic issue concerns the compatibility between the national constitutional law of EAEU Members and their obligations under the EAEU legal framework, especially in the cases of Russia and Belarus. The former has rather activist courts, which have and still can challenge the authority of the EAEU Court; while the latter effectively allows for the Constitutional Court to check the compatibility of decisions of the Commission with national laws and decrees. It is argued in this chapter that some of the concerns can be mitigated through an increased interinstitutional dialogue between the judicial authorities and a ‘living document’ constitutional interpretation. The ability of the EAEU Court to fulfil its aim of ensuring uniform application and interpretation of Union law is the main focus of Chapter 6. It is illustrated that some basic judicial remedies available in the EAEU are similar to those in the EU. However, most importantly, it is also established that procedures, crucial for legal order autonomy, are absent and no suitable substitutes to replace them are available. Thus, there is no viable mechanism ensuring uniform application and interpretation of Union law in all Member States; and the Commission cannot challenge Member States’ infringements in the Court. It is argued in the chapter that these challenges are the hardest to overcome. Nevertheless, it is demonstrated that, in particular, regardless the absence of a provision on exclusive jurisdiction, the Court’s kompetenz-kompetenz to determine its jurisdiction coupled with the duty of loyal cooperation can play a key role in establishing it. Further, it is argued that the limitation on the creation of new norms by the Court is virtually impossible to uphold in practice. Overall, this research demonstrates that the EAEU fulfils certain requirements of an autonomous legal order. In the first place, it complies with the essential preconditions through its system of Union law and international legal personality. There are also certain manifestations of the indicia of legal order autonomy. In particular, the supranational effect of legal norms is manifested in an established direct applicability of a range of rules: the EAEU Treaty establishes direct applicability of Commission decisions and the Court has already interpreted competition law provisions as well as certain international agreements as directly applicable. It does not automatically mean that this will lead to the recognition of a full-fledged direct effect in the legal order of EAEU Member States, although the Court is seemingly moving in this direction. The Court has also started incorporating the discourse of primacy in its rulings, which is not necessarily in line with the approach of the Member States’ judiciary. Nevertheless, the lack of an advanced mechanism ensuring uniform application and interpretation of Union law in all Member States (i.e. preliminary ruling) is the gravest concern for legal order autonomy as it endangers the ability of the legal order for self-maintenance. Moreover, coupled with the Commission’s inability to prosecute Member States, this increases the risk of misapplication of Union law and fragmentation of the legal system. The Court is also limited in its ability to interpret the powers of the Union as certain of its interpretations can be overruled by the Member States, and there is a clear restriction on vesting institutions with new powers (i.e. implied powers). However, this research demonstrates that the former has its limits and the latter can be overcome without encroachment on the principle of attributed powers. Institutional supranationality is almost non-existent in the EAEU, with the exception of the Commission Board and the Court. The issue whether Union law is of self-referential character is more controversial and is subject to continued monitoring of the development of the EAEU legal discourse. However, there are indications that favour this reading at least when the internal dimension of legal autonomy is concerned. To conclude, the EAEU legal order is without doubt far from the same type of legal order autonomy developed in the case law of the Court of Justice of the European Union. The EAEU possesses a number of similar autonomy features allowing to say that the organization has a limited autonomy of the legal order. Nevertheless, it has troubles demonstrating some of the indicia. Even though this research demonstrates that certain limitations can be mitigated through interpretation, others are beyond the scope of pure interpretative powers and require Treaty amendments.