Negative self-esteem is an important transdiagnostic factor underlying various youth psychological problems. Most studies so far have examined the role of more conscious, explicit self-esteem, assessed with self-report questionnaires. Our study investigated the role of explicit as well as implicit self-esteem (with Rosenberg's self-esteem scale and the implicit association test, respectively), and the nature of their interaction in explaining children's and adolescents' internalizing symptomatology. Self-esteem, depression, and anxiety symptoms were assessed in 279 youths (mean age: 13.92; 52% females). Explicit self-esteem (ESE) was consistently negatively related to internalizing symptoms, whereas implicit self-esteem (ISE) was not. For DSM-related anxiety symptoms, the interaction between ISE and ESE was significant: in youths who displayed low to average ESE, higher ISE predicted more anxiety symptoms, whereas for youths with high ESE, increased ISE was associated with lower levels of anxiety symptoms. Overall, our results suggest that explicit self-esteem is an important factor in explaining internalizing symptomatology for children and adolescents.