This study addresses the relationship between corporate biodiversity reporting (CBR) and earnings management as well as the moderating impact of board gender diversity (BGD). Due to increased regulatory pressure, we relied on a sample of STOXX Europe 600 firms (1,537 firm-year observations) for the business years 2017–2021. In line with the moral licensing hypothesis, we assume that CBR and our two main proxies of earnings management (accruals-based and real earnings management) are positively related, and a critical mass of female directors may weaken this link. Our regression results align with these assumptions and prior research on similar relationships. Moreover, we conduct several endogeneity checks, which support our main results. This study mainly contributes to prior research as it is the first one on the link between CBR and earnings management. We stress major implications for researchers, standard setters, and business practitioners. Biodiversity represents a key sub-pillar of sustainability reporting with an impact on financial reporting, indicating the need for integrated thinking, which should be promoted in future empirical research.