The article explores the concept of accountability in European governance, aiming to define it clearly and assess its various forms. Accountability is defined as a relationship between an actor and a forum, where the actor must explain and justify their actions, the forum can question and judge, and the actor may face consequences. The article identifies several types of accountability, including political, legal, administrative, professional, and social accountability, each with distinct characteristics and forums. It also discusses the challenges of accountability, such as the problem of many eyes (multiple forums with different criteria) and the problem of many hands (multiple actors contributing to policy implementation). The article presents three evaluative perspectives: democratic, constitutional, and learning. The democratic perspective emphasizes public control and transparency, the constitutional perspective focuses on preventing corruption and abuse of power, and the learning perspective aims to enhance government effectiveness through accountability mechanisms. The article concludes that accountability is crucial for maintaining the legitimacy of governance, ensuring that public institutions remain effective and responsive to the needs of citizens.The article explores the concept of accountability in European governance, aiming to define it clearly and assess its various forms. Accountability is defined as a relationship between an actor and a forum, where the actor must explain and justify their actions, the forum can question and judge, and the actor may face consequences. The article identifies several types of accountability, including political, legal, administrative, professional, and social accountability, each with distinct characteristics and forums. It also discusses the challenges of accountability, such as the problem of many eyes (multiple forums with different criteria) and the problem of many hands (multiple actors contributing to policy implementation). The article presents three evaluative perspectives: democratic, constitutional, and learning. The democratic perspective emphasizes public control and transparency, the constitutional perspective focuses on preventing corruption and abuse of power, and the learning perspective aims to enhance government effectiveness through accountability mechanisms. The article concludes that accountability is crucial for maintaining the legitimacy of governance, ensuring that public institutions remain effective and responsive to the needs of citizens.