ABSTRACT This paper investigates education policy reform in post-Devolution Wales with a focus on school accountability. Specifically, it provides a historicist analysis of Wales’ decision to abandon publicly mandated school league tables and subsequent accountability reforms. The paper uses the literature on four governance models to investigate successive accountability regimes in Wales through time. These have changed from a Trust and Altruism model, via a Transparent Public Rankings model, to a new, emerging model that relies on self-assessment and collaborative accountability standards. Notably, the Organization for Economic Cooperation and Development (OECD) has played an increasingly important role in shaping this process. Central to our analysis is Mark Bevir and Roderick Rhodes’ decentered theory. The paper argues that governance models need to be understood with reference to the dynamic interplay of historical constraints, power struggles and new belief systems that respond to policy dilemmas. As Wales has embarked on several substantial education policy reform initiatives, the paper demonstrates the importance of a historically informed approach to policy design and implementation which is responsive to competing traditions and beliefs.