Transparency-based global environmental governance, like all global governance, necessarily plays out in national contexts. Its efficacy is shaped not only by global politics but also by the norms and capacities prevailing within countries. Over the past two decades, there has been an extraordinary upheaval in transparency views and practices in numerous countries, rich and poor, democratic and authoritarian. This multi-faceted development has been driven by such varied factors as democratization, privatization, and changing views about appropriate regulatory practices. These changes provide the crucial context for understanding the transparency transformation that is currently unfolding within global environmental governance, as well as what its promise, limitations and implications in practice might be in diverse national contexts.