A cross-sectional study of 3426 referred children and adolescents showed that the presence of both migration history and family dysfunction was associated with a fourfold (95% CI 2–9) higher risk of psychotic symptoms compared with the absence of these factors. The relative risk was 2 (95% CI 1–4) for migration history only. Interaction between migration history and family dysfunction accounted for 58% (95% CI 5–91%) of those with psychotic symptoms. These results suggest a relationship between family dysfunction and migration in the development of psychosis.