Background Childhood internalizing symptoms can be associated with adolescent internalizing symptoms, but only a small proportion of symptomatic children are at long-term risk. Our objectives were to (1) distinguish between typical and atypical levels of internalizing symptoms using mother- and teacher-assessments and (2) test the association between childhood internalizing symptoms and adolescent generalized anxiety, depression, and social phobia symptoms in boys and girls. Methods Multi-trajectory models were used to estimate the evolution of mother- and teacher-reported internalizing symptoms across childhood (1.5 to 12 years) in a large population-based cohort (n = 1431). Multiple linear regression models were implemented to estimate the association between childhood group membership of internalizing symptoms and self-reported specific internalizing symptoms at 15 years by sex. Results Five groups of childhood internalizing symptoms were identified: Mother & teacher low (22.6%), Mother moderate/teacher low (37.9%), Mother moderate/teacher high (18.3%), Mother high/teacher low (11.8%) and Mother & teacher high (9.5%). Multiple linear regression models showed that compared to the low group, (1) boys in the high group reported higher social phobia symptoms (p = 0.04), (2) girls in the high group reported higher depression (p = 0.01) and generalized anxiety (p < 0.01) symptoms, and (3) girls in the moderate/high group reported higher generalized anxiety symptoms (p = 0.02) in adolescence. Limitations The main limitation is that mothers’ and teachers’ assessments mostly covered different developmental periods. Conclusions A multi-informant assessment of childhood internalizing symptoms improves adolescent specific internalizing symptoms identification in a general population sample over reliance on a single informant.< Réduire