ENIn recent years, pension funds have experienced a noteworthy global shift towards integrating sustainability considerations into their investment strategies. This shift demonstrates the recognition of potential risks and opportunities associated with environmental, social, and governance (ESG) factors. This paper critically reviews pension fund sustainability metrics and reporting systems, focusing on the growing interest among pension funds worldwide in incorporating ESG factors into their investment strategies. It explores the motivations driving pension funds to invest in sustainable assets, the challenges they encounter, and the potential benefits associated with such investments. The findings indicate that pension fund investments in sustainable assets can significantly contribute to promoting sustainable development and responsible investment practices. By incorporating ESG factors into their investment strategies, pension funds can effectively manage risks, enhance long-term returns, and generate positive societal impact. However, to maximize the potential benefits of sustainable investing for pension funds and society at large, challenges related to measurement, limited investment diversity and expertise, as well as the standardization of metrics and reporting systems for sustainable investing, need to be addressed. Key Words: Pension fund, sustainability, sustainable assets, investment, ESG. [From the publication]