This study analyses the relationship between prison moral and social climate and reoffending. It relates data from the measuring the quality of prison life (MQPL) survey carried out in all prisons in England and Wales to official data on proven reoffending from the Ministry of Justice. The sample contains data from 224 prison surveys conducted between 2009 and 2013 (a total of 24,508 prisoners completed the survey). Results indicate that several of the MQPL dimensions were found to be related to rates of proven reoffending for each prison. As the MQPL survey measures the moral, relational and organizational quality of prison life for prisoners, overall these findings suggest that higher moral quality of life, or higher interior legitimacy, supports better outcomes for prisoners on release. This is consistent with theoretical expectations about the links between legitimacy, engagement in prison programs, well-being, and compliance with the law.