This paper examines the potential of green finance instruments and mechanisms to support the growth and scaling of green startups. Using a secondary-source-based methodology, the study synthesizes policy reports, academic literature, and institutional case studies (UNEP, World Bank, Climate Bonds Initiative, Kumar et al., Mudalige, Huang et al.) to identify effective financing channels, successful practices, barriers, and knowledge gaps. The analysis highlights that while green finance — including green bonds, concessional finance, blended finance, impact investing, and specialized green venture funds — has expanded rapidly, direct flows to early-stage green startups remain constrained by information asymmetries, high perceived risk, weak pipelines, and regulatory fragmentation. Case studies from municipal green bonds, blended-finance facilities, and fintech-enabled green bond issuance illustrate pathways to mobilize capital. The paper concludes with policy and practical recommendations to strengthen market infrastructure, enhance de-risking, and build capacity, and outlines areas for future research.