The experiences of lesbian, gay, bisexual and transgender (LGBT) students in schools have been under-documented. For this reason, a third national survey was conducted by the Gay, Lesbian and Straight Education Network (GLSEN). As in previous surveys, LGBT youth were asked about biased language in their schools, feelings of comfort and safety in school, and experiences of verbal, physical and sexual harassment based on sexual orientation, gender, gender expression, race/ethnicity, disability and religion. Students who reported incidents of harassment or assault were also asked whether they had reported these events to school personnel or to family members, and whether family members ever intervened with the school. Other questions posed included the usefulness of school-based resources and support groups (i.e., gay-straight alliances), and the effect of school climate and resources on academic achievement and educational goals. A total of 887 lesbian, gay, bisexual or transgender youth between the ages of 13 and 20 from 48 states and the District of Columbia completed the survey. The results from this 2003 National School Climate Survey echo the findings from prior surveys--for many of our nation's LGBT youth, school can be an unsafe and even dangerous place. The majority of the LGBT youth in our study heard homophobic remarks frequently, felt unsafe in school because of their sexual orientation and reported being verbally harassed because of their sexual orientation or their gender expression. A large number of youth also reported experiencing incidents of physical harassment, physical assault, sexual harassment and deliberate damage to personal property. The findings from this survey also demonstrate that transgender students feel particularly vulnerable because of their gender expression. (Includes 33 footnotes, 2 tables and 90 figures.)