In the current socioeconomic context, the question of local government sustainability transparency is of great interest to policymakers, managers, citizens and other stakeholders, and yet one to which previous research has devoted little specific attention. At the same time, the Internet has become an instrument of good governance worldwide and government entities in Europe have strived to promote e-government to improve transparency towards citizens. The aim of this study was to identify factors that can help politicians and managers improve practices of sustainability information disclosed by European local governments. To do so, an empirical study was conducted of 91 municipalities in nine countries, comparing three main administrative cultures. Our analysis of the study results highlights various demographic, socioeconomic, financial and legal factors that may be useful to policymakers and managers in promoting the online provision of sustainability information in Anglo-Saxon, Nordic and Southern European countries.