Numerous recent studies have demonstrated that schools are often unsafe for lesbian, gay, and bisexual (LGB) adolescents, who are more likely than heterosexual peers to be bullied, harassed, or victimized in school contexts. Virtually all of these studies call for change, yet none investigate whether or not it has occurred. Using repeated waves of a population-based high school survey, we examine (a) the extent to which sexual orientation differences in school bullying and violence-related experiences are reported by lesbian/gay, bisexual, and heterosexual male and female adolescents; (b) trends in school bullying and violence-related experiences for each gender/orientation group; and (c) whether disparities have changed over time. Data were drawn from 8 Massachusetts biennial Youth Risk Behavior Surveys from 1999 to 2013, grouped into 4 waves totaling 24,845 self-identified heterosexual, 270 lesbian/gay, and 857 bisexual youth. Disparities between LGB and heterosexual peers were found in all indicators. Heterosexual youth and gay men saw significant reductions in every outcome between the first and last waves. Among bisexual men, skipping school because of feeling unsafe, carrying weapons in school, and being bullied all decreased, but among lesbians and bisexual females only fighting in school declined significantly. Improvement trends in school safety were more consistent for heterosexual youth and gay males than for bisexual or lesbian females. Notably, despite these improvements, almost no reduction was seen in sexual orientation disparities. Future research should identify influences leading to reduced school victimization, especially focusing on ways of eliminating persistent sexual orientation disparities.