Lean government is all about doing better with less through the use of ICT and the realisation of process improvements. The recently introduced eXtensible Business Reporting Language (XBRL) has shown some initial success in realising lean government. Once data is stored in XBRL format, businesses can transmit it electronically to government for reporting purposes. For businesses, XBRL will increase both corporate accountability and transparency by reducing the time needed to collect, structure and share corporate data within the company, as well as with supply chain partners, investors and government agencies. Government agencies will benefit from higher information quality (no data rekeying in the reporting chain) and new forms of compliance monitoring requiring fewer resources. Yet, because of the complexity of standardising processes, data and infrastructure in a publicprivate information exchange, the full potential of this ‘sleeping giant’ is often left dormant in practice. Drawing on the best practice of Standard Business Reporting (SBR) in the Netherlands, this paper shares some critical success factors derived from the move towards a lean government in the country. Eight critical success factors (CSFs) focusing on the transformation process are identified. While the scope and elaboration of the factors is limited to business-to-government (B2G) reporting, the possibilities for lean government are broader, opening new avenues for governments and researchers.