Sustainable finance has rapidly evolved into a central pillar of the global financial system, driven by the urgent need to address climate change, environmental degradation, and widening social inequalities. Green bonds differ from conventional bonds primarily in their earmarked use of proceeds and enhanced transparency requirements. Issuers—ranging from governments and multilateral institutions to corporations and financial entities—commit to allocating funds exclusively to environmentally sustainable projects and often adhere to internationally recognised standards, such as the Green Bond Principles. Parallel to the rise of green bonds, ESG-aligned investment strategies have become integral to modern portfolio management. These strategies extend beyond traditional financial analysis by systematically integrating non-financial factors that influence long-term performance and risk exposure. The study covers the period from 2015 to 2025, capturing the rapid expansion phase of green bonds and the increasing adoption of ESG frameworks globally. It seeks to answer key research questions like the contribution of green bonds to sustainability, the impact of ESG integration on investment performance and the challenges faced for the effective implementations of sustainable finance A descriptive and analytical research methodology has been adopted, based on secondary data collected from reports of financial institutions, international organizations, and existing literature. Comparative analysis has been used to evaluate the performance and effectiveness of green bonds and ESG strategies. In conclusion, the integration of green bonds and ESG-aligned investment strategies signifies a transformative shift in the philosophy and practice of finance. By aligning capital flows with sustainability objectives, these instruments and approaches not only contribute to environmental protection and social well-being but also foster more resilient, transparent, and future-oriented financial systems. As innovation, regulation, and investor awareness continue to advance, sustainable finance is poised to play a pivotal role in achieving global development goals and facilitating the transition to a low-carbon, inclusive economy.