ISSUE:  The role of family acceptance as a protective factor for lesbian, gay, bisexual, and transgender (LGBT) adolescents and young adults has not been established. METHODS:  A quantitative measure with items derived from prior qualitative work retrospectively assessed family accepting behaviors in response to LGBT adolescents' sexual orientation and gender expression and their relationship to mental health, substance abuse, and sexual risk in young adults (N= 245). FINDINGS:  Family acceptance predicts greater self‐esteem, social support, and general health status; it also protects against depression, substance abuse, and suicidal ideation and behaviors. CONCLUSIONS:  Family acceptance of LGBT adolescents is associated with positive young adult mental and physical health. Interventions that promote parental and caregiver acceptance of LGBT adolescents are needed to reduce health disparities.