This thesis examines the political economy of the Taxonomy for Sustainable Investments, a European Union binding legal act intended to direct privatecapital toward economic activities that are environmentally sustainable. As a key pillar of the EU’s broader climate and sustainable finance strategy - and in alignment with the objectives of the EU Green Deal - the EU Taxonomy is a central tool in the Union’s efforts to reduce carbon emissions and build a climate- friendly and environmentally sustainable economy by 2050. Through a political economy lens, this thesis explores how institutional actors, EU Member States, the financial sector, environmental NGOs, and science expert bodies have shaped, supported, and opposed the Taxonomy. Their different stances on natural gas and nuclear power and environmental and climate policy resemble and foreshadow their different takes on energy security and economic development. After analyzing all the stakeholders that have influenced and are being influenced by the Taxonomy, the changes that were implemented, the reasons why its content was reformulated and how the current market structure received it, a conclusion is reached. The EU Taxonomy aims to protect the climate and the environment – as was intended – but it is also being used to fulfill geopolitical goals, economic growth and industry lobbying.