Intergovernmental Organisations (IGOs) have been playing a prominent role in the Open Educational Resources (OER) movement in advocating for and supporting the development of governmental OER policies. Research shows that IGOs perform multiple roles in influencing national and global education policy processes and possess multiple policy instruments with which they can assert their influence. We adopted the conceptual framework of policy instruments to understand the types of policy instruments applied by the selected IGOs. We carried out semi-structured interviews with representatives from four important IGOs. Results show that the selected IGOs collectively used discursive dissemination, funding, technical assistance, standard-setting and coordinative functions OER policy instruments to influence the development of governmental OER policies. We report on the perceived and observed successes of these IGOs OER policy instruments and the related challenges. We discuss relevant findings and their implications for further research and activities of IGOs.