While the importance of biodiversity is starting to become clear for managers and organizations, our understanding of what biodiversity means for business and how best to disclose it remains limited. The purpose of this study is to examine how biodiversity is justified and argued for in companies’ sustainability reports. More specifically, the study focuses on what kinds of justifications are used and what is considered worthy and valuable in biodiversity reporting. We apply the conventionalist analysis to examine how biodiversity is justified in the sustainability reports of the mining sector and to reveal the socially accepted rationales the companies draw from in their biodiversity communication. The study contributes to the literature on biodiversity communication by showing how the common worlds of justification are used in sustainability reporting and how they bring forth certain assumptions and values while hindering others.