This study evaluates private sector engagement in the UNFCCC process and other international processes and presents options for improved engagement. It reviews the existing business engagement practices in the UNFCCC process, and evaluates the lessons learned and the areas where the private sector could engage more constructively. This study also reviews business engagement models outside the UNFCCC. To evaluate the views of stakeholders on private sector participation, the study provides a summary of outcomes from five global workshops and surveys. Finally, the study proposes options for private sector engagement in the intergovernmental process, and the principles and criteria that need to be considered. Illustrative options for private sector engagement in the UNFCCC process are also provided.