Neurodevelopmental disorders of Attention-Deficit/ Hyperactivity Disorder (ADHD) and Oppositional Defiant Disorder (ODD) are extremely common but underserved with Evidence-Based Treatments (EBT) worldwide. Thus, our team developed, implemented and evaluated a school clinician training and ADHD/ODD intervention (i.e., the Collaborative Life Skills [CLS] program) for Mexico: a setting with high unmet need. We integrated technology into our in-person program (CLS-FUERTE) to create a digitally-enahnced version (CLS-R-FUERTE). Given findings demonstrating feasibility, acceptability, and efficacy of both program versions, we propose a Type 2 Hybrid Effectiveness-Implementation Design to evaluate the program effectiveness, mechanisms of intervention change, and maintenance barriers/facilitators in a scaled-up cluster randomized controlled trial with n = 40 schools across two Mexican -while also- exploring the impact of an implementation strategy in which we adapt the program to fit each school’s needs/resources during the maintenance period to encourage sustainability (i.e., CLS-A-FUERTE). Our implementation process is guided by the Exploration, Preparation, Implementation, and Sustainment (EPIS) model with evaluation following the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) Framework. Aim 1) Test the effectiveness and implementation of the CLS-A-FUERTE school clinician training and ADHD/ODD intervention program adapted for schools across Mexico. We expect: H1) School clinicians will engage in training and implement chosen intervention components with fidelity H2) Teachers and/or families will engage in chosen intervention components and adhere to the strategies H3) Students receiving CLS-A-FUERTE will show greater improvement in ADHD/ODD symptom and impairment severity (rated by parents/teachers) compared to students receiving school services as usual Aim 2) Evaluate mechanisms of sustained intervention change. We expect: H4) Improvements in parenting behaviors will mediate sustained intervention effects H5) Improvements in teacher and/or school clinician competency will mediate intervention effects Aim 3) Identify CLS-A-FUERTE maintenance barriers and facilitators. We expect across adaptations that sustained intervention effects and continuation of program activities at follow-up will relate to: H6) Program feasibility (i.e., cost estimates) and acceptability (i.e., participant satisfaction) H7) Characteristics of participating schools and school context factors Aim 4) Expand research capacity to a novel university setting. We expect emerging investigators will: H8) Complete clinical research coursework and produce deliverables (i.e., presentations, papers, grants) H9) Show improved EBT skills, research capacity and culture ratings, and competency as program trainers