From an international perspective, a relationship between public sector transparency and better economic and social outcomes is something that is increasingly acknowledged. In terms of lack of transparency in budget reports both bureaucratic model and fiscal illusion theory have been argued as explanations. To assess transparency in budget practices we analyse to what extent a sample of 41 countries are meeting OECD requirements according to its Best Practices for Budget Transparency document (OBP). We find an average OBP fulfilment of 56.4 per cent. Transparency is negatively correlated with corruption and positively correlated with economic development. Countries receiving external financial and technical support meet fewer OBP recommendations than countries not receiving it. Considering the political framework, both progressive and conservative governments reach similar transparency levels. OECD members do not significantly fulfil more OBP suggestions than non-members. In respect of 4 variables: transparency, corruption, democracy and development, four clusters of countries arise: top-performing, low transparency-developed, low transparency-developing and worst-performing.