In 1999, GLSEN identified the need for national data on the experiences of lesbian, gay, bisexual, and transgender (LGBT) students and launched the first National School Climate Survey (NSCS). At the time, the school experiences of LGBT youth were under-documented and nearly absent from national studies of adolescents. For more than a decade, the biennial NSCS has documented the unique challenges LGBT students face and identified interventions that can improve school climate. The survey explores the prevalence of anti-LGBT language and victimization, the effect that these experiences have on LGBT students' achievement and well-being, and the utility of interventions in lessening the negative effects of a hostile school climate and promoting a positive educational experience. The survey also examines demographic and community-level differences in LGBT students' experiences. The NSCS remains one of the few studies to examine the school experiences of LGBT students nationally, and its results have been vital to GLSEN's understanding of the issues that LGBT students face, thereby informing our ongoing work to ensure safe and affirming schools for all. In our 2011 survey, we examine the experiences of LGBT students with regard to indicators of negative school climate: