Since the adoption of the UN Guiding Principles on Business and Human Rights the relationship between human rights due diligence (HRDD) and corporate liability has been a source of legal uncertainty. In order to clarify this relationship, this article compares and contrasts civil liability provisions aiming at implementing HRDD. It explains the legal liability mechanisms in the draft Treaty on Business and Human Rights and in domestic mandatory HRDD legislation and initiatives such as the French Duty of Vigilance Law and the Swiss Responsible Business Initiative. It compares these developments with the emerging case law on parent company and supply chain liability for human rights abuses. It explores the potentially perverse effects that certain civil liability provisions and court decisions might have on companies’ practices. Finally, it makes recommendations for the design of effective liability mechanisms to implement HRDD.