Introduction: Child mental health is a critical public health issue, with disorders such as anxiety and depression affecting up to 20% of children worldwide. Early detection and effective interventions are essential to mitigate the effects of these disorders and improve the quality of life of affected children. This study conducted a systematic review to identify the most effective strategies for early detection and interventions in childhood anxiety disorders and depression. Methods: The systematic review was conducted in the PubMed, Scopus, PsycINFO, and Web of Science databases, using descriptors such as “Child Mental Health,” “Early Detection,” “Anxiety Disorders in Children,” and “Childhood Depression.” Empirical studies published between 2010 and 2024 were included. Study selection was performed by two independent reviewers, and methodological quality was assessed using the AMSTAR tool and the Newcastle-Ottawa Scale. Results: Thirteen studies were included that indicate the effectiveness of instruments such as the "Spence Children's Anxiety Scale" (SCAS) and the "Child Depression Inventory" (CDI) in the early detection of anxiety and depression in children. Interventions based on Cognitive-Behavioral Therapy (CBT) and multidisciplinary approaches were effective in reducing symptoms and improving the quality of life of children. However, the implementation of these strategies faces significant challenges, such as lack of resources and the need for cultural adaptations. Conclusion: Early detection and timely interventions are essential for the effective management of anxiety disorders and depression in children. The importance of public policies for training professionals and intersectoral collaboration to ensure quality mental health care is reinforced. Future research should focus on culturally adapted interventions and evaluate their long-term effectiveness.