Students of organizational behaviour have always been concerned with understanding the manner in which complex organizations – including systems of public administration – tend to create distinctive organizational cultures and the impact these cultures have on their activities and outputs, including their prospects for reform. Recently, neo-institutional accounts of social and political life have provided a new entry point to the analysis of administrative cultures and administrative reform. For neo-institutionalists, the institutional structure of an organization creates a distinct pattern of constraints and incentives for state and societal actors that define and structure actors’ interests and channel their behaviour. The interaction of these actors generates a particular administrative logic and process, or “culture”. However, since institutional structures vary, a neo-institutional perspective suggests that there will be many different kinds of relatively long-lasting patterns of administrative behaviour, each pattern being defined by the particular set of formal and informal institutions, rules, norms, traditions and values, and many different factors affecting the construction and deconstruction of each pattern. Following this neo-institutional logic, this article develops a multi-level, “nested” model of administrative styles and applies it to patterns of convergence and divergence in administrative reform in many jurisdictions over the past several decades