Abstract: Universities in developing countries have rarely been able to subscribe to academic journals in the past. The “Online Access to Research in the Environment” initiative (OARE) provides institutions in developing countries with free online access to more than 5,700 environmental science journals. Here we analyze the effect of OARE registration on scientific output by research institutions in five developing countries. We apply a difference-in-difference estimation method using panel data for 18,955 journal articles from 798 research institutions. We find that online access via OARE increases publication output by at least 43% while lower-ranked institutions located in remote areas benefit less. These results are robust when we apply instrumental variables to account for the information diffusion process and a Bayesian estimation method to control for self-selection into the initiative.