This study was designed to assess the effects of religion and two types of religious internalization on the mental health of Iranian adolescents. High school students (82 Moslem and 37 Christian) were selected randomly from four high schools in Shiraz and completed the Religious Self-regulation Questionnaire and the General Health Questionnaire. Analysis showed that main effects of types of religious internalization measured on four subscales of the General Health Questionnaire were significant. Religion was significantly associated only with somatic symptoms. For other scales no main effects of religion, types of religious internalization, or their interactions were significant.