<p>This study examines the impact of ESG peer pressure on corporate green transformation and its underlying mechanisms within horizontal and vertical networks, using non-financial enterprises listed on China’s A-share market from 2009 to 2023 as the research sample. Findings reveal that horizontal ESG peer pressure promotes green transformation: when other firms in an industry exhibit generally superior ESG performance, it encourages the target firm to pursue green transformation actively. Vertical ESG peer pressure similarly drives green transformation: when other enterprises in a company’s supply chain demonstrate superior overall ESG performance, it encourages the firm to pursue green transformation actively. Mechanism tests reveal that horizontal ESG peer pressure facilitates green transformation by enhancing corporate ESG performance, whereas vertical ESG peer pressure does so by increasing green investment. Heterogeneity analysis indicates that ESG peer pressure within horizontal and vertical networks exerts a more substantial propulsive effect on green transformation for firms with higher absorptive capacity, operating in more competitive markets, and belonging to non-heavily polluting industries. The research conclusions offer novel insights and perspectives to accelerate corporate green transformation and achieve high-quality economic development.</p>