This chapter explores social media's potential to enhance public involvement to pursue sustainable practices on an international scale across planning and development projects. Using a case-study approach, the international institutions of the World Bank, UN-Habitat, Unilever, and World Business Council for Sustainable Development are investigated. The relationship between public versus the institutions' intake on sustainability is examined. Findings identify strong public push for increased sustainability in international development and show evidence of the ways in which international institutions respond to the public. Contributing to the social media research field, it offers an alternative application to the planning profession via e-planning. This could contribute to an extended form of public engagement through social media that goes beyond the limiting geographical borders of each local community, and assesses planning and development projects for their broader sustainability implications on an international platform.