Sexual and gender minority (SGM) adolescents are more likely to become victims of bullying and harassment than heterosexual, cisgender adolescents, but little is known about the contextual details of these victimization experiences. This study aims to examine by whom and where adolescents are bullied or harassed, to whom adolescents report such victimization, and whether these experiences differ between SGM and heterosexual, cisgender adolescents. Methods: Participants in this nationally representative study were 29,879 students (mean age ¼ 14.1) from 136 Dutch middle/high schools across grades 7e12 (14.5% sexual minority, 2.7% gender minority) who completed a survey about their school-based experiences. Results: Perpetrators of victimization of SGM students were more often teachers and school staff compared with heterosexual, cisgender adolescents. Furthermore, SGM students experienced victimization in private locations (in the rest-or changing rooms/parking lots, at home), more often than heterosexual, cisgender students. Finally, SGM students felt less safe than their heterosexual, cisgender peers to report these experiences to teachers or parents, and were more likely to report their experiences to the police or the school janitor. SGM students who reported victimization experiences were less likely to receive support: the problems were less often acted on and persisted more often than those of heterosexual, cisgender students. Conclusions: SGM adolescents are not only victimized more often, but also by different perpetrators (teachers, other school staff) and in more private places. Their victimization is also less likely to be recognized or acted on by those responsible for adolescent's safety: teachers or parents.