Book excerpt: This report, Ending slavery in Mauritania: The impact of legal advocacy and strategic litigation from 2010 to 2020, provides an assessment of the activities undertaken by Minority Rights Group (MRG), Anti-Slavery International (ASI) and SOS-Esclaves in the decade 2010–20, focusing on strategic litigation activities, domestic-level litigation and international litigation. The organizations have worked closely together during this time to campaign for an end to slavery in Mauritania, a practice that continues despite being criminalized. First, the report presents key events that have supported the change in the legal landscape in Mauritania and offers an overview of the roles played by organizations involved in the fight against descent-based slavery. Second, it looks at the theories of change of the different stakeholders involved in action to define the impact of advocacy and strategic litigation activities. It then goes on to analyse the impact and outcomes of the use of judicial and quasi-judicial mechanisms. The final section offers items for reflection, discussion and strategic planning.