Transparency is today considered as a key feature of good governance. Almost undisputed, the concept has gained importance in both academic and practitioners’ circles due to its strong intrinsic and/or instrumental value. Recent years have seen the emergence of the open-data movement and its growing impact on government policies. Nevertheless, evidence related to impacts on transparency remains fragmented. This study aims to contribute to the field of research on transparency and open data by providing a conceptual clarification and by showing how both concepts are related and perceived in the Swiss public administration. This allows avoiding further confusion and better understanding the relation between the two notions. Moreover, this contribution also explores the implementation of the open-data logic in Switzerland. Although it does not participate in the Open Government Partnership, an international platform of 75 governments committed to making their activities more transparent, the country launched the federal Open Government Data project in 2015 with the aim of establishing an open-data culture within the administration. However, implementation of the open-data logic has been rather halting so far. Based on in-depth interviews conducted with civil servants in Switzerland, this contribution identifies four main types of barriers that impact on the uptake of open data in Switzerland: cultural, institutional, individual and economic.