Corporate due diligence has been at the core of responsible business practices for decades. In recent years, there has been an increased shift beyond the narrow focus on financial compliance towards a broader concept of due diligence that incorporates sustainability issues.

This paper explores the role credible sustainability systems have been playing in supporting corporate due diligence to date. We begin by defining due diligence, distinguishing between voluntary and mandatory frameworks, and outlining the key requirements for businesses. The core of the paper examines how robust sustainability systems contribute to effective risk assessment and management, holistic stakeholder engagement, robust monitoring and reporting, and continuous improvement within companies and their supply chains. We then illustrate how these contributions align with the traditional steps of due diligence outlined by the Organisation for Economic Co-operation and Development (OECD). Finally, we summarise the interplay between sustainability and corporate due diligence in today’s increasingly regulated global environment.