This article seeks to explain cross-country variation in noncompliance with European law. Although noncompliance has not significantly increased over time, some European Union member states violate European law more frequently than others.To account for the observed variance, the authors draw on three prominent approaches widely used in the compliance literature— enforcement, management, and legitimacy. They develop hypotheses for each of these approaches before combining them in theoretically consistent ways. They empirically test their hypotheses using a comprehensive data set of more than 6,300 violations of European law.The findings highlight the importance of combining the enforcement and management approaches. Powerful member states are most likely to violate European law, whereas the best compliers are small countries with efficient bureaucracies. Yet administrative capacity also matters for powerful member states. The United Kingdom is much more compliant than Italy, which commands similar political power but whose bureaucracy is far less efficient.