Drawing on minority stress theory, this study examined the mental health effects of the added burden of disadvantaged social status in an Israeli sample of 461 self-identified lesbian, gay, and bisexual (LGB) youths. Bisexuality was associated with lower levels of well-being, and, at a younger age, with higher levels of mental distress. In bisexuals, this relationship was fully mediated by family support and acceptance, internalized homophobia, and LGB social contact. Religiosity was associated with low levels of family and friends' support and acceptance, and high levels of internalized homophobia. These findings highlight the mental vulnerability of LGB adolescents and bisexuals, as well as the social vulnerability of sexual minorities in the religious sector, and the importance of social support to increase mental health. (Contains 2 tables and 3 figures.)