Study of informal organizations in prisons in Latin America focuses on the exercise of control over daily life inside detention centers, including the extreme example of ‘self-government’ of and by those incarcerated. In Latin America, self-government occurs in the dangerous context of severe overcrowding, limited resources and poor services, aggravated by high levels of violence and illicit markets within prisons. The combination is highly volatile and poses grave dangers to the lives and wellbeing of detainees, authorities and often the larger society beyond prisons. This article considers one pioneering effort to overcome the unfettered control of prison by detainees: the Peruvian Prison Reform Process of 2011-2019. The article examines the situation before the ReformProcess, one marked by high levels of violence, riots, escapes and inmate self-rule. The transformation of Peruvian prisons considered here managed to end self-government, replacing it with a system based on peaceful dialogue, recognition of legitimate representatives of inmate organizations, and restoration of order and non-violence. The ReformProcessreduced and eliminated prison riots, shootings, the taking of hostages and strikes by workers. The Reform Process led to a drastic reduction in the number of violent deaths and prison escapes. Based on the success of the Peruvian model and a review of other experiences in Latin America, the article proposes four models of prison management. For ungovernable detention centers, it proposes recognition of legitimate inmate organizations, dialogue and respect for human rights as the most effective means of reducing violence and lawlessness.