AbstractThis study employs a two‐way fixed effects model to investigate the influence of bank competition on ESG performance of local firms and its underlying mechanisms based on the geographical distribution of bank branches and firms. Our results show that the increased level of competition among banks contributes positively to the ESG performance of firms and the promotion effect is more prominent in small firms, young firms, and nonstate‐owned firms. Industry heterogeneity analysis indicates that bank competition could be more beneficial for the sustainable development of low‐pollution, low‐tech industries, and industries that have a higher linkage with the financial industry. The mechanism analysis further reveals the mediating effect of financial constraints, green innovation, and moral hazards on firms' ESG performance. This study extends the existing understanding of the firm‐level consequences of bank competition and sheds light on the financial development drivers of corporate ESG performance in emerging market countries.