Policy adaptation of new members of European Union occupied a focal point in the European political development after the end of the Cold War, particularly during the eastward enlargement of the EU. The author argues that there is a strong correlation between EU enlargement and policy adaptation in the context of Europeanization. Drawing on learning theory, an explanation of policy adaptation is offered on the basis of two different sub-theories: the social learning theory model, which emphasizes the legitimacy of rules and process; and the lesson-drawing model, which focuses on Policy Dissatisfaction, epistemic communities, and transferability of rules. The environmental policy of Czech Republic provides evidence for applicability of the learning process hypothesis of European values and norms.