Transgender high school students (those whose gender identity differs from their sex assigned at birth) experience disparate health outcomes and challenges in school, including violence and discrimination, compared with cisgender students (those whose gender identity aligns with their sex assigned at birth). Until recently, population-based data describing the experiences of transgender students and students questioning whether they are transgender (questioning) have been limited. In 2023, the national Youth Risk Behavior Survey assessed transgender identity, providing the first nationally representative data about transgender students. This report describes the demographic characteristics of transgender and questioning high school students and examines differences in the prevalence of experiences of violence, poor mental health, suicidal thoughts and behaviors, school connectedness, and unstable housing among transgender, questioning, and cisgender high school students nationwide. In 2023, 3.3% of U.S. high school students identified as transgender, and 2.2% identified as questioning. Transgender and questioning students experienced a higher prevalence of violence, poor mental health, suicidal thoughts and behaviors, and unstable housing, and a lower prevalence of school connectedness than their cisgender peers. Compared with 8.5% of cisgender male students, 25.3% of transgender students and 26.4% of questioning students skipped school because they felt unsafe. An estimated 40% of transgender and questioning students were bullied at school, and 69% of questioning students and 72% of transgender students experienced persistent feelings of sadness or hopelessness, a marker for experiencing depressive symptoms. Approximately 26% of transgender and questioning students attempted suicide in the past year compared with 5% of cisgender male and 11% of cisgender female students. Intervention opportunities for schools to create safer and more supportive environments for transgender and questioning students can help address these disparities. The findings of this report suggest that more effort is necessary to ensure that the health and well-being of youths who are socially marginalized is prioritized.