Abstract As an independent country, Estonia can decide on how to promote its economy through state intervention, at least in theory. At the same time, Estonia has been a WTO member since 1999 and an EU Member State since 2004 and must adhere to these rules. Both regimes limit a Member State’s ability to interfere in the economy, setting forth rules on when a state can interfere with consequences if the rules are not met. But these rules differ, and the same situation can have a different result depending on the rules applied. Also, both sets of rules limit the competence of a member country to interfere in economy differently, for example, the WTO applies a rather lenient ex post control while in the EU a strict ex ante control by the Commission is used. Also the consequences for failing to adhere are different. Although one of the smallest EU Member States and represented by the Commission in WTO roundtables, it is still relevant for Estonia to have a position on globally applied state interference measures, and present and protect its views, if needed. To successfully promote its economy nationally and in the EU, Estonian policymakers, like those of any other country in the same position, must know not only the applicable state interference rules but also the underlying principles thereof. The article will provide a historical overview of the framework of the supranational state aid regimes of the WTO and the EU, as well as the domestic rules of Estonia. It is aimed at reflecting the principles behind the state aid rules that the domestic policymakers must consider when designing national state interference measures. The author applies classical research methods, namely, reading and interpretation of texts, but also comparing the WTO, EU and Estonian laws on state subsidies.