Legislatures’ “power of the purse”, the ability to tax and spend public money, is enshrined in constitutions worldwide as a cornerstone of legislative power in democratic countries. Their role across the budget cycle is a fundamentally important national concern, lying at the heart of issues such as transparency, inclusiveness and democratic accountability. Despite different historical, constitutional, and political contexts, common features for parliaments to play an effective role in budgeting have emerged from experiences across OECD countries.