Government subsidization has historically started to be frequently and systematically adopted during the mercantilist period from the XVI and the XVII century, although in some countries it goes back even longer. This period was characterized by the introduction of new production and commercialization methods. The merchant class was vested with great power, and often used such power to provide political institutions with suggestions and requests. Indeed, political support was a fundamental element of companies’ survival and growth because states had the power to affect the market and promote the competitiveness of national companies. A broad array of strategies and measures could lead to this result — including the adoption of discriminatory tax regulations and quotas against foreign products and companies in favor of domestic industries. In Europe, mercantilism developed at a time when the economy was in transition, after centralized nation-states successfully replaced the previous feudal system. Moreover, technological innovation in the transportation sector — and in particular in shipping — together with increasing urbanization, led to a rapid and exponential growth in international trade. The function of mercantilism was twofold: on the one hand, it focused on how international trade could bend to serve the interests of nation-states, while on the other it explored ways for national governments to contribute to domestic companies’ trade and business development. Those were the years that saw the adoption of modern accounting. The latter allowed precise and constant monitoring of trade inflows and outflows, creating the necessity of maintaining a positive trade balance, which could be achieved by ensuring that exports were higher than imports. This was possible thanks to the introduction of new domestic products that could effectively replace traditionally imported ones. During the liberalist period — characterized by a laissez-faire economic policy — public subsidies were set aside, while they revived at the end of the XIX century when protectionism enjoyed a new vogue. Since then, subsidies have been used by governments both to promote national economic, social, and political policy as well as to correct market distortions. It is generally recognized that subsidies often produce harmful effects on free trade and production rather than equitable results, and international trade law has taken into account all these concerns in drafting specific rules on subsidies. In this contribution, we are going to draw the attention on the effects of subsidies, distinguishing subsidies which are necessary for desirable and acceptable purposes from those that are nothing but disguised protectionist measures and that might trigger international trade remedies. In particular, this evaluation will be applied to renewable energy subsidies. Governmental support to alternative and renewable energy industry represents a fairly common choice for governments in need to comply with the commitments that bind them within the international framework for climate change. Besides being a common choice, renewable energy subsidies represent an effective one: according to the Intergovernmental Panel on Climate Change (IPCC), “one of the most effective incentives for fostering greenhouse gas (GHG) reductions are the price supports associated with the production of renewable energy, which tend to be set at attractive levels. These price supports have resulted in the significant expansion of the renewable energy sector in countries belonging to the Organization of Economic Cooperation and Development (OECD) due to the requirement that electric power producers purchase such electricity at favorable prices.” This contribution is divided in four sections. The first one (section 2), offers a brief description of the evolution of the World Trade Organization (WTO) regulation of subsidies, while in the second one (section 3) we analyze the approach of the WTO towards renewable energy subsidies, focusing on specific issues, such as the case of feed-in tariffs and local content requirement. Section 4 provides an overview of WTO disputes involving subsidies in the renewable energy sector, and Section 5 focuses on the recent decisions in the Canada — Renewable Energy and Canada — Feed-in Tariff Program disputes. Finally, we draw some conclusions.