Using a sample of Chinese A-share listed firms from 2010 to 2023, this study examines how ESG peer effects and firms’authentic and imitative behaviors influence audit fees. The empirical results show that ESG peer effects significantly reduce audit fees, and this reduction is driven primarily by firms engaging in genuine ESG imitation. Further mechanism analyses reveal that genuine ESG imitation reduces audit fees by mitigating firms’operational and litigation risks. The heterogeneity analysis shows that the effect of genuine ESG imitation on reducing audit fees is more pronounced in firms with verified ESG reports, independently disclosed ESG information, non-heavily polluting industries, competitive industries, low economic policy uncertainty, and a high level of rule of law. Overall, this study enriches the understanding of the economic implications of ESG peer effects and their behavioral authenticity, offering theoretical insights for regulators seeking to enhance ESG oversight and improve audit quality.