Background: Despite widespread recognition of its prevalence and consequences, depression in nursing homes remains a significant public health issue, affecting 15-25% of community nursing home residents and contributing to increased morbidity, mortality, care burden, and cost of care. In VA Community Living Centers (CLCs) the prevalence of depression is nearly 40% and within the first six months of discharge, CLC residents have a substantially higher risk of suicide compared with other age- and gender-matched VA users. In accordance with VA’s Strategic Priority to prevent suicide, it is critical to explore approaches to reducing depression that are specific to the CLC population because depression is a major risk factor for suicidality. Evidence-based psychosocial treatments are not often used in nursing homes and, when used, little is known about the quality or effectiveness of the interventions. Behavioral Activities Intervention (BE-ACTIV) is a 10- week evidence-based psychosocial intervention for depression developed using nursing home staff and resident input to build in feasibility and acceptability. BE-ACTIV is typically delivered by a mental health therapist in collaboration with recreational therapy to engage residents in personally meaningful pleasant activities. This type of approach to improving mental health care is in line with VA’s strategic goals to provide timely and integrated care that emphasizes Veteran’s well-being and independence. Objectives: Three gaps must be addressed before BE-ACTIV can be used successfully in CLCs: (1) Adapting it for the short-stay CLC population, is largely male with higher prevalence of serious mental illness and substance abuse disorders, (2) Developing a delivery strategy that adapts BE-ACTIV’s current in-person training and oversight processes for the context of a complex, national system of nursing homes, and (3) Comparing implementation strategies to facilitate regional or national roll out. We will compare onsite and remote applications of the LOCK implementation framework, which was developed for use in the CLC context. The four tenets of the LOCK implementation framework are: 1) Look for the bright spots, 2) Observe, 3) Collaborate in huddles, and 4) Keep it bite-sized. Methods: This Hybrid Type 2 Implementation-Effectiveness study will use a mixed methods approach. In Aim 1, at two CLCs, researchers will (a) conduct telephone interviews with CLC staff about adaptation of the BE- ACTIV training materials and implementation guide and (b) test the adapted BE-ACTIV VA training materials and implementation guide for user comprehensibility with CLC staff. In Aim 2, 6 sites will implement BE-ACTIV VA, each over a 6-month period. For this, three sites will have onsite training and check-ins for the implementation and three will have remote training and check-ins. Aim 3 will be dedicated to finalizing the training materials and implementation guide based on the input received from staff, our advisor...