Public procurement represents a substantial economic lever within emerging economies, offering immense potential to drive green economic development through strategic market influence. However, conventional procurement metrics predominantly prioritise immediate cost savings and operational efficiency failing to adequately capture the crucial environmental and broader socio-economic contributions essential for sustainable transformation. This misalignment hinders effective mobilisation of public spending towards achieving national green growth programs and international sustainability commitments like the United Nations Sustainable Development Goals (UNSDGs). This chapter aims to identify and propose procurement Key Performance Indicators (KPIs) that effectively measure and promote green economic outcomes within the unique contexts of emerging economies. To achieve this, the chapter pursues three key objectives: (1) critically assess the effectiveness of existing public procurement performance metrics in promoting environmental sustainability in emerging economies, (2) identify key challenges and gaps in designing and implementing environmentally focused procurement metrics and (3) synthesise international best practices and emerging innovations in green procurement measurement relevant to developing contexts. The research identifies critical gaps by employing a systematic literature review (SLR) of Scopus, Web of Science, and Google Scholar academic databases supplemented by grey literature (UN, governments publications) from 2012 to 2025. Key findings reveal that current metrics undervalue long-term environmental benefits, lack standardisation for green outcomes, offer insufficient strictness for monitoring progress, and often neglect social co-benefits integral to green development. Consequently, the chapter recommends the strategic integration of outcome-based environmental KPIs (lifecycle carbon footprint, percentage spend on certified sustainable goods/services), socio-economic indicators (job creation in green sectors, local sustainable supplier development), alongside robust data collection systems and capacity building for procurement entities. By redefining value through optimised metrics, this chapter provides a practical roadmap for policymakers and procurement practitioners to transform procurement into a powerful, measurable catalyst for inclusive and sustainable economic development in developing economies.