This paper outlines the barriers to private sector investment and engagement, and to capital mobilization, into climate mitigation and adaptation related sectors and projects in developing countries. Based on an analysis of barriers by sectors and countries, and supported by examples, the paper proposes general strategic elements for interventions by the Green Climate Fund’s Private Sector Facility (PSF) where there is evidence of a market gap. The final part of the paper comprises recommendations to the Board from Private Sector Advisory Group (PSAG) on overcoming these barriers, based upon their discussion of the Secretariat’s analysis.