PROJECT SUMMARY/ABSTRACT Many evidence-based preventative interventions have been developed to prevent substance use, physical and mental illness, and promote positive educational and social outcomes among adolescents. Among these, caregiver-mediated interventions boast strong effects that are mediated by effective parenting skills. However, the impact of these interventions is severely limited by low rates of home practice of intervention skills among caregivers. To address this research-to-practice gap, researchers have been investigating barriers and facilitators of caregiver engagement, focusing in large part on intervention attendance. Strategies for increasing caregivers' home practice of skills remain underexamined. Yet, caregiver home practice is a key component of theorized intervention effectiveness and has been found to impact parenting behaviors and subsequent child outcomes over and above that of attendance. Therefore, the next important step in supporting parenting behavior change is to develop implementation support strategies for evidence-based interventions that target caregiver home practice specifically. This K01 Mentored Research Scientist Development Award will develop and pilot a digital behavior change intervention for use as an adjunct to an evidence-based preventative intervention. The digital behavior change intervention aims to increase caregivers' home practice of intervention skills. Informed by the theory of planned behavior, habit formation principles, and relapse prevention theory, the intervention will leverage mobile health technologies (mHealth) to circumvent and problem solve common barriers to home practice including home practice intention, frequency of practice, home practice competence, and maintenance of intervention skills. The intervention will be developed as a smartphone application (i.e., “app”) with components informed by a qualitative assessment of barriers to caregiver home practice and refined through direct stakehol