Mental disorders in children and youth are on the rise worldwide, affecting approximately one in five young people in Europe. The negative educational, social and economic consequences of mental health problems underline the urgent need for accessible, high-quality mental health services. In response, the WHO Regional Office for Europe has developed Quality Standards for Child and Youth Mental Health Services to provide a framework for evidence-based, youth-centred care. Previous efforts have shown that translating quality standards and guidelines into practice remains a major challenge. While implementation science offers valuable approaches to improving the uptake of evidence-based quality standards and has been successfully applied in various healthcare fields, it remains underutilised in child and youth mental health care. This article explores how implementation science can be leveraged to improve the quality of child and youth mental health care. Using the implementation of the WHO European Quality Standards for Child and Youth Mental Health Services as a practical case example, we highlight the importance of a structured approach to implementation, guidance by theories, models and frameworks, timely stakeholder engagement, and context-specific adaptation. Harnessing implementation science in youth mental health policy and practice has the potential to bridge the gap between policy formulation and real-world service delivery, ensuring that all young people receive the high-quality mental health care they deserve.