This paper traces the progressive shift at the international level from purely voluntary approaches (corporate social responsibility or CSR) towards accountability mechanisms to ensure the environmentally sound conduct of private entities. It examines whether the most recent international discussion on human rights and corporate accountability have adequately considered environmental protection concerns. It then concentrates on the growing number of international oversight mechanisms that provide a readily-available and impartial avenue for addressing complaints against private companies for their negative environmental impacts. The paper concludes that certain key standards elaborated within the framework of the Convention on Biological Diversity, in particular environmental-cultural impact assessments and benefit-sharing, are increasingly referred to in the decisions of different international corporate accountability mechanisms to ensure both the protection of the environment and of human rights.