ABSTRACT As achieving corporate environmental goals increasingly depends on the green efforts of suppliers, focal firms are now widely recognized as key actors in driving suppliers' green innovation. Drawing on legitimacy theory and signaling theory, this paper investigates how buyers' environmental information disclosure influences suppliers' green innovation from a supply chain perspective and further explores the moderating role of buyer–supplier relationship characteristics. Utilizing a dyadic dataset comprising buyer–supplier pairs of Chinese A‐share listed firms between 2008 and 2021, the study applies panel data regression techniques to test the proposed hypotheses. The findings illustrate that buyers' environmental information disclosure significantly promotes the green innovation of their suppliers, and this positive relationship is strengthened under conditions of higher buyers' power and a higher level of common institutional ownership. This study broadens the understanding of buyers' impact on suppliers' green innovation by emphasizing the role of public environmental disclosure as a form of indirect buyer–supplier interactions and also extends knowledge about the moderating factors that influence suppliers' decisions from a relational view. Thus, this study contributes to the existing literature on sustainable supply chain management and buyer–supplier relationships.