Since the 1980s, there has been a significant rise in domestic and international efforts to enforce individual criminal accountability for human rights violations through trials, but we still lack complete explanations for the emergence of this trend and the variation observed in the use of human rights prosecutions in the world. In this article, we examine the role that procedural law has had in allowing societal actors to influence in this rising trend for individual criminal accountability. We do this by focusing on participation rights granted to victims, such as private prosecution in criminal cases. Based on an exploration of an original database on human rights prosecutions in Latin America and fieldwork research in three countries, we argue that private prosecution is the key causal mechanism that allows societal actors to fight in domestic courts for individual criminal accountability for human rights violations.