Children are considered gifts and play a central role in American Indian (AI) culture. However, AI children are at elevated risk for experiencing poverty, parental mental health disorders, household exposure to substance use, domestic violence, and maltreatment, all of which increase their risk of poor mental and physical health outcomes as adolescents and adults. Virtually no evidence-based programs exist that can be administered in a resource-poor tribal setting, can be culturally adapted, can be exported, and hold promise for sustainability. The needs of these vulnerable AI children, thus, remain almost entirely unmet. Decades of research have shown that secure attachment in infancy and early childhood is a key developmental building block that predicts adjustment and promotes resilience in children who grow up under stressful circumstances. Because secure attachment develops from caregiver sensitivity and responsiveness, it is critical to address caregiver sensitivity in early childhood. We will, therefore, test the Promoting First Relationships (PFR) program, a theoretically driven, relationship- and strengths-based primary prevention program. Several studies have shown the diverse positive effects of PFR on the caregiver-child relationship for at-risk populations. The University of Washington Partnerships for Native Health have nurtured a strong, long term collaboration with the Fort Peck Tribes, whose reservation lies in a remote area of northeastern Montana. The tribes' Elders Involved Initiative has stated that the health and well-being of children and young adults are their primary concern, recommending a return to traditional parenting values. With our tribal partner, we will adapt PFR to ensure cultural appropriateness, then conduct a randomized, controlled trial to compare the PFR intervention with a control group receiving information on resources and referrals. Our primary purpose is to test the effectiveness of PFR in improving the caregiver's sensitivity to the child (primary outcome). We will also examine child attachment security to the caregiver and the child's social and emotional functioning. Our specific aims are to 1) adapt the PFR intervention using focus groups; 2) assess the adequacy of training by examining the pre- and post-training attitudes and consultation strategies used by community-based PFR providers with caregivers and infants; and 3) compare the PFR and control group on caregivers' sensitivity and responsiveness and children's social and emotional competencies and attachment security. Effective primary preventive interventions are critically needed for AI children who grow up under stressful circumstances. By promoting sensitive caregiving and child attachment security, we can minimize the impact of contextual stressors on children living on the Fort Peck reservation and, foster resilience, and improve their risk outlook.