Stakeholder engagement between researchers, policymakers and practitioners is critical for the successful translation of research into policy and practice. The Counseling and Testing for Children at Home (CATCH) study evaluated a paediatric index case testing model, targeting the children of HIV-infected adults in care in Kenya. Researchers collaborated with stakeholders in the planning, execution and evaluation, and dissemination phases of CATCH. They included a community advisory board, the national HIV programme, County health departments, institutional ethics review bodies, a paediatric bioethics group, facility heads and frontline healthcare workers . Stakeholder analysis considered the power and interest of each stakeholder in the study. All stakeholders had some power to influence the success of the project in the different phases. However, support from institutions with higher hierarchical power increased acceptance of the study by stakeholders lower in the hierarchy. During the planning, execution and evaluation, and dissemination phases, the study benefitted from deliberate stakeholder engagement. Through engagement, changes were made in the approach to recruitment to ensure high external validity, placing recruitment optimally within existing clinic flow patterns. Choices in staffing home visits were made to include the appropriate cadre of staff. Adaptations were made to the consenting process that balanced the child’s evolving autonomy and risks of HIV disclosure. Dissemination involved delivering site-specific results in each HIV clinic, local and international conferences and sharing of study tools, resulting in the study approach being scaled up nationally. The deliberate engagement of stakeholders early in intervention development optimized study validity and accelerated adoption of the CATCH approach in nationwide HIV testing campaigns by the Ministry of Health and inclusion of paediatric index-case testing in national HIV testing guidelines. Involving policymakers and frontline healthcare workers throughout the study cycle builds capacity in the implementing team for quick adoption and scale-up of the evidence-based practice.