Since the emergence of the REDD+ mechanism, hundreds of projects have emerged around the globe. Much attention has been given to REDD+ projects in the literature, but the conditions under which they are likely to be efficient ares till not well known. In this article, we study how the location of REDD+ projects is chosen and how those location choices influence project additionality. Based on a sample of six REDD+ projects in Brazil, we propose an empirical analysis of the location choices and estimate additionality in the first years of implementation using impact evaluation techniques. In order to explain the heterogeneity of the empirical results, we present a simple theoretical model and show that project location is strongly influenced by the type of project proponent, which appears to be a good proxy for its objectives, whether oriented toward environmental impacts, development impacts, or external funding. Our results suggest that (1) the incentives behind REDD+ certification mechanisms can lead to low environmental efforts or an investment in areas that are not additional, (2) location biases are dependent on the REDD+ project manager’s type, and (3) the existence of a location bias does not necessarily preclude additionality.