The objective of the current thesis was to increase our understanding of the ethnic differences in mental health service use for adolescents’ internalizing problems. In the first part of the thesis, we examined whether questionnaires assessing adolescents’ internalizing problems could be validly used across ethnic groups and more specifically whether the diagnostic utility of the instruments was comparable across four ethnic groups (i.e., native Dutch, Surinamese-Dutch, Turkish-Dutch, and Moroccan-Dutch). In the second part of the thesis, we focused specifically on the ethnic differences in mental health service use for adolescents’ internalizing problems and attempted to unravel the mechanisms underlying these differences following the steps toward mental health care proposed by Cauce and colleagues (2002; i.e., problem recognition, decision to seek help, service selection). In our study, we used a two-phase study design. In the first phase of the study adolescents were screened on internalizing problems to include sufficient adolescents at risk of internalizing problems in the second phase of the study. For the second phase of the study, adolescents from the four largest ethnic groups in the Netherlands were selected to participate. The final study sample of the second phase of the study consisted of 95 native Dutch, 85 Surinamese-Dutch, 87 Turkish-Dutch, and 82 Moroccan-Dutch parents and adolescents. In the four ethnic groups, about half of these adolescents scored in the borderline/clinical range on the internalizing problem scale during the screening, which indicates that adolescents in the four ethnic groups were similarly at risk of internalizing problems. Results of the first part of the thesis provided support for the validity and diagnostic utility of the instruments used to compare internalizing problems across ethnic groups among adolescents, whereas the results indicated that the diagnostic utility of these instruments was insufficient among immigrant parents, specifically among Moroccan-Dutch ...