Despite the unsatisfactory progress under the UNFCCC, the REDD + debate has raised hopes for successfully tackling the unsustainable use of forests in developing countries. However, its approach of focusing on the sequestration capacity of forests is potentially at odds with other environmental objectives. In order to cope with the risk of unintended impacts on biodiversity, the UNFCCC agreed on environmental safeguards that have yet to be specified and implemented through national REDD + strategies. Employing theoretical considerations regarding non-binding institutions and transparency, we investigate whether and how the voluntary setting of the REDD + Partnership can support the development of effective environmental safeguards. The analysis shows that the Partnership, despite its non-binding features, represents a promising complementary policy approach to the UNFCCC. Consisting of public and private actors it has laid the foundation for a more comprehensive view on REDD + by focusing on information exchange on practical implementation issues, e.g. on the specification of the safeguards agreed under the UNFCCC. If efforts to ensure accountability through transparency and stakeholder inclusiveness can be further improved, the setting may significantly contribute to establishing horizontal accountability, and hence, trigger a ‘race to the top’ on environmental standards.