Immigrant youth comprise a sizable and integral part of contemporary societies. Their successful adaptation becomes a high‐stakes issue for them and for society. In spite of the challenges they face, most of them adapt well in their new countries. In this article, I examine the question of who among immigrant youth succeeds and why, based on findings from a three‐wave longitudinal project conducted in Greece. That study found that immigrant youth were less well adapted initially with respect to major developmental tasks (academic achievement, conduct, peer acceptance) and were less engaged in school than their nonimmigrant classmates, but that they did not have less optimal psychological well‐being. These findings held for all ethnic groups and generations. Family functioning and immigrant youth's attributes contributed to individual differences in their adaptation. These results may reflect at least partly societal attitudes toward the presence of immigrants in the country.