This report examines the prison system in Libya. With the permission of the Libyan Ministry of Justice and Judicial Police, United States Institute of Peace (USIP) research teams conducted two assessments of the Libyan prison system, visiting detention facilities throughout the country in 2012 and again in 2015–16 to evaluate organizational function, security, infrastructure, and prisoner well-being. This report combines and compares the findings of the two assessments, discussing the broader context of detention issues in Libya, with analysis centering on prisons under the authority of the Ministry of Justice and operated by the JudicialPolice. The2012assessmentteamconsistedof Fiona Mangan, a USIP senior program officer, and Dr. Mark Shaw, an expert consultant. The 2015–16 assessment team consisted of Rebecca Murray, a researcher and journalist; Rami Musa, a journalist; and Fiona Mangan. Mohamed Abouharous provided invaluable translation and logistical support during both visits. The assessments, part of a multiyear portfolio of rule of law programming and analysis conducted after the 2011 revolution, were supported by the International Narcotics and Law Enforcement Bureau of the U.S. Department of State.