PEUTRANSP investigates the determinants of transparency activity in the European Parliament (EP). Legislative transparency has become a key condition to improve the quality of democracy: it is a prerequisite of democratic accountability and legitimacy, an antidote against corruption and a key ingredient of good governance. In the EU context, recent research has investigated how transparency regimes are designed and why certain political actors perform more transparently than others. However, the determinants of transparency-related activity encompassing both the one supplied by the EP in policy-making and the one demanded by the EP from third parties are not well-known. The project addresses transparency from this broader perspective. Research strategies will be based on quantitative methods and combine diverse types of data sources. The results will contribute to better understand the logics and practice of transparency regimes at the EU level and its implications in terms of democratic quality.