ABSTRACT The failure of traditional mental health services to significantly reduce the disproportionate involvement of people with serious mental illnesses (SMI) in the criminal justice system highlights a basic but overlooked fact: mental illness is not a primary driver of criminal justice involvement. Research has consistently shown that people with mental illness face the same risk factors for justice involvement (i.e., “criminogenic” risk factors) as those without mental illnesses. Research has also found that justice-involved people with SMI have high levels of criminogenic risk factors and that these risk factors mediate their risk of recidivism. Yet, most interventions for justice-involved people with SMI do not target criminogenic risk factors as a goal of treatment. This gap between research and service provision represents untapped potential to reduce rates of justice involvement among people with SMI, by expanding their continuum of services to include interventions that directly target criminogenic risk factors. Our recent NIMH-funded randomized controlled trial (1R34MH111855-01; PI: Wilson) demonstrated that when adapted for use with people with SMI, criminogenic-focused interventions can successfully engage key treatment targets and outcomes associated with criminogenic risk factors among prisoners with SMI. Given that up to 50% of people with SMI receiving treatment in the community-based mental health system have had some criminal justice system involvement, developing criminogenic-focused interventions for delivery in community mental health settings has great potential to optimize their potential impact, both in terms of the numbers of people with SMI who can benefit and in terms of potential reductions in future criminal justice involvement. This R34 proposal brings together a team of nationally recognized experts to engage a deployment-focused approach to the development and preliminary testing of a new, scalable, and sustainable group-based, criminogenic-focused cognitive-behavioral therapy intervention developed specifically for use among people with SMI in community-based mental health settings. This proposed study includes three aims. The first aim will engage user-centered design methodologies to optimize the development of the new intervention. The second aim will conduct a small pilot randomized controlled trial to test the preliminary effectiveness of the new intervention. This pilot trial will engage an experimental therapeutics approach to examine how the new intervention engages the intended treatment targets and outcomes. The third aim will use qualitative research methods with key stakeholders to identify implementation strategies that both maximize and expediate the scalability and sustainability of the new intervention in community based mental health settings.