Correctional environments are unique as settings in which people are confined involuntarily, possibly for very long periods of time, and not for their own welfare. As such they can be very difficult places to endure. Moreover, inmates and staff are exposed to multiple environmental stressors whose effects may be magnified by the time of exposure and the difficulty in avoiding them. Inmates commonly need to cope with lack of privacy, high levels of crowding, isolation from needed human contact, constant high levels of noise, poor lighting conditions (too little in the daytime and too much at night), and little access to nature or nature views. New models of correctional design, with increased direct contact between inmates and staff, and greater control over environmental conditions, have had success in reducing violent behavior in recent decades. A model of environmental determinants of violence is presented that attempts to explain this success.