Samples of 867 Greek adolescents in Munich, 2,702 Greek adolescents in Greece and 2,780 Turkish adolescents in Turkey were assessed concerning mental health in a two-stage procedure. In the first stage the General Health Questionnaire (GHQ) was used for screening. Significant age differences in the GHQ 28-item scale and most of its subscales were observed mainly for the samples in the homeland. Male adolescents had lower scores than female adolescents in the GHQ 28-item scale and its sub-scales while social class appeared to be of little influence. Significantly higher GHQ-28 scores were obtained for Greeks and Turks in their homeland as compared to Greeks in Turks in their homeland as compared to Greeks in Munich. The GHQ-28 correlations with the Anorexia Nervosa Inventory for Self-Rating were fairly high. A principal component analysis with Varimax rotation showed fairly consistent results for this age group when compared with the results of Goldberg and Hillier (1979). With the exception of the GHQ factor social dysfunction Greek adolescents in their homeland had significantly higher scores in the total GHQ-28 and its sub-scales than Greeks in Germany. Thus, our data do not confirm the acculturation-stress hypothesis. The data would be consistent with the hypothesis of selective migration which states that Greek adolescents in Germany constitute a positive selection with respect to risk for mental illness.