Stress-and-coping frameworks predict increasing psychological adaptation of immigrants over time, but although previous studies found evidence for this assumption in adult samples, this temporal pattern was hardly found among adolescent immigrants. The authors argue that in adolescent immigrants an acculturation-related increase in psychological adaptation over time might be counterbalanced by an age-typical decrease in indicators of psychological adaptation. This longitudinal study, covering a 3-year period in mid-adolescence, compared change in depressed mood as an indicator of psychological adaptation in three matched samples of 101 newcomer adolescent immigrants, 101 more experienced adolescent immigrants, and 101 native adolescents. Results showed that native adolescents and experienced adolescent immigrants increased in depressed mood, as is typical for this age group, over the 3-year period. Newcomer adolescent immigrants, however, remained stable, reporting more depressed mood initially than the more experienced immigrants. Moreover, the extent of depressed mood reported by newcomer and more experienced adolescent immigrants converged over time. This pattern of results indicates that both age-typical development and acculturation need to be considered when drawing conclusions on change in psychological adaptation over time in immigrant populations.