Abstract OBJECTIVE: To compare the rates of all Axis I and II mental disorders and suicide attempts in sexual orientation minorities with rates in heterosexuals using a nationally representative sample. METHOD: Data used were from the National Epidemiologic Survey on Alcohol and Related Conditions Wave 2 (n = 34 653, response rate = 70.2%). Cross-tabulations and multivariate logistic regression analyses were performed to determine differences in rates of mental disorders and suicide attempts by sexual orientation. All analyses were stratified by sex. RESULTS: Compared with their heterosexual counterparts, lesbians and bisexual women demonstrated a 3-fold increased likelihood of substance use disorders, and gay and bisexual men showed twice the rate of anxiety disorders and schizophrenia and (or) psychotic illness, even after accounting for mental disorder comorbidity. Suicide attempts were independently associated with bisexuality, with odds 3 times higher than in heterosexuals. CONCLUSION: Findings from our study emphasize the fact that sexual orientation minorities are vulnerable to poor mental health outcomes, including suicide attempts. Clinicians need to be aware of these specific negative mental health consequences when assessing sexual orientation minorities.