Criminologists have long claimed that states of deprivation engendered by restrictive prison environments account for much of the problematic behavior that occurs there. It is logical to assume that any efforts to provide greater access to meaningful and appropriate activities may therefore serve to reduce such behavior by altering motivating operations for misconduct and occasioning reinforcement for other types of behaviors. Given the higher rates of trauma exposure and other mental health issues in prison populations, considering trauma-informed practices in intervention design is prudent. The current study evaluated the effects of environmental enrichment via prisoner-selected, peer-led activities conducted during association times. We used direct observation to assess engagement, existing facility data collection to detect changes in problematic behavior, and prisoner and staff surveys to assess perceptions of the overall acceptability and effects of the intervention. Prisoners engaged with and led a range of activities, with the majority reporting positive effects on behavior, social relationships, and general well-being; staff responses were generally positive but more tempered. Institutional behavior records did not appear sensitive enough to detect treatment effects. We discuss the results in terms of integrating trauma-informed care into prison interventions and the need to develop more robust measures of behavior change.