Most U.S. children living in out of home care (OOHC) have debilitating impairments regulating emotions and behavior and the success of treatment efforts for these children depends principally on caregivers’ capacity to provide developmentally enriching, therapeutic care. While living in OOHC, the adults who care for these children during the critical hours outside of formal therapy play central roles in their treatment. Yet, OOHC caregivers receive little education about how to meet the unique relational needs of the children they serve and lack a clear understanding of their own therapeutic role in each child’s rehabilitation. In addition, the most commonly-used training programs for caregivers in OOHC cover an eclectic range of topics without a specific focus on relational skills, and few have empirical support. Ultimately, in order for OOHC services to optimize children’s rehabilitation and mitigate the long-term sequelae of developmental trauma, it is imperative to provide opportunities for caregivers to develop skills for eliciting developmentally enriching interactions (DIs) during their ordinary care routines. Toward that goal, we propose two specific aims. Aim #1: Produce a video- based Developmental Interaction Workshop Series (DIWS) that enables caregivers to repeatedly observe and practice specific forms of DI and to create opportunities to increase their frequency during daily care routines. The DIWS will include two 4-hour sessions for caregivers and supervisors, as well as two 90-minute sessions for supervisors. A beta version will be implemented in one Residential Care (RC) agency, revised as needed, and then fully implemented in three RC agencies. Aim #2: Evaluate the DIWS using mixed methods (staff and child surveys, staff interviews, and ethnography) in four RC agencies to document preliminary evidence of its impact, acceptability, and feasibility. We expect the DIWS to lead (1) caregivers to become more capable, motivated, and purposeful about eliciting DIs in their caregiving role, and (2) caregivers and children to perceive a greater prevalence of DIs during routine daily activities. We will also identify individual, organizational, and implementation-related factors related to uptake. The DIWS will provide a developmentally-informed framework for understanding and enhancing the child-adult relationships in OOHC. Mixed-method evaluation results will provide the foundation for future RCTs of the program’s efficacy, inform program improvements, and facilitate its wider dissemination.