For many lesbian, gay, bisexual, and transgender (LGBT) youth, intolerance and prejudice make school a hostile and dangerous place. This study examined simultaneously the effects of a negative school climate on achievement and the role that school-based supports--safe school policies, supportive school personnel, and gay-straight alliance (GSA) clubs--may have in offsetting these effects. Data were drawn from a survey of a diverse sample of 5,730 LGBT youths who had attended secondary schools in the United States. Results from structural equation modeling showed that victimization contributed to lower academic outcomes and lower self-esteem; however, school-based supports contributed to lower victimization and better academic outcomes. Moderating effects of supports on esteem and academic outcomes were also examined through hierarchical linear regression. Results suggested that a hostile school climate has serious ramifications for LGBT students but institutional supports can play a significant role in making schools safer for these students.