PURPOSE: To examine differences in unstable housing and health-risk behaviors and experiences by sexual identity among U.S. high school students. METHODS: Using data from the 2021 Youth Risk Behavior Survey, a nationally representative survey of U.S. high school students, we calculated prevalence estimates and prevalence ratios of unstable housing by sexual identity (lesbian, gay, bisexual, questioning, and other-identifying [LGBQ+] vs. heterosexual). Among students experiencing unstable housing, we calculated prevalence estimates and prevalence ratios by sexual identity for substance use, violence victimization, mental health, and suicidal behaviors. RESULTS: LGBQ+ students were twice as likely to experience unstable housing, including sleeping in shelters or emergency housing, compared to heterosexual students. Among students experiencing unstable housing, LGBQ+ students were more likely to use substances and experience violence victimization, poor mental health, and suicide ideation and attempts. DISCUSSION: LGBQ+ youth experience a disproportionate burden of unstable housing and related health-risk behaviors and experiences.