This chapter is devoted to analysing the evolution and significance of ESG indicesESG indices on the Polish capital marketPolish capital market over their 15 years of operation. Particular attention is given to two indices of the Warsaw Stock ExchangeWarsaw Stock Exchange: the RESPECT IndexRESPECT Index—the first Socially Responsible InvestingInvestment (SRI) index in Central and Eastern Europe—and its successor, the WIG-ESG IndexWIG-ESG Index. Their composition, methodology and investment performance were examined, with a focus on their impact on the development of responsible investing in Poland. The chapter places Polish experiences in a broader context, also presenting selected global ESG indices and comparing their efficiency and market functions. Both the positive effects of the operation of ESG indices, including the increase in investor awareness and the promotion of responsibility standards, and the limitations resulting from methodological difficulties in assessing the actual commitment of companies to sustainable development, were discussed. The discontinuation of the WIG-ESG Index in 2024 marks a critical juncture for reflecting on the future of ESG instruments on the Warsaw Stock Exchange. The analysis highlighted the need for further development of non-financial reporting support, enhanced education of market participants and deeper integration of ESG factors into investment decision-making in order to more effectively advance sustainable development goals.