The paper concerns the issue of responsible involvement of commercial banks in Poland in green financing of the energy sector. The main reason for undertaking this topic is the observed increased interest of domestic banks in green financing of investments on the energy market in Poland. Therefore, the main objective are to explore the determinants of changes in the level and structure of bank loans under the influence of green investments in the energy sector in Poland. The article verifies the research hypothesis which assumes that an increase in financing green investments by bank loans in the energy market in Poland requires strengthening the synergy of responsible financing of sustainable development of the economy. For this purpose, a two-stage concept of the empirical research was adopted. On the first stage, questionnaire surveys were conducted among the largest Polish commercial banks to examine the respondents’ acceptance degree of the concept of sustainable financing and greening the loan portfolio. On the second stage, case studies were analyzed along with the analysis of selected secondary quantitative data. It was proven that commercial banks in Poland increase their commitment to sustainable financing, which is observed in the sectorally progressing process of “greening” the credit offer. There is also a noticeable change in their approach to social responsibility, especially in the context of the energy market, where financing of traditional, ecologically harmful projects is still dominant. However, this trend is slowly being reversed, towards supporting investments in the area of modern, environmentally-friendly energy solutions. However, “greening” of loan portfolios in the native banking sector requires a responsible lending policy based on various complex business decisions. Increasing their pro-ecological awareness of financing the economy is only a prerequisite, albeit inadequate, of further energy transformation in Poland.