Many bystander programs to prevent violence have been developed and evaluated in college populations. An exception is the randomized controlled trial of Green Dot, found effective in reducing violence rates and violence acceptance in 26 high-schools (2010-2014). In 'Life's Snapshot', 10,727 seniors were recruited from these same schools with the goal of determining the longer-term efficacy of bystander training. Students in intervention schools could have up to three years of Green Dot exposure. Seniors from intervention versus control schools had significantly lower scores (p <0.01) indicating less violence acceptance or sexism for two of five measures. Seniors' self-reports of bystander training received confirmed these findings. These cross-sectional analyses suggest that some reductions in violence acceptance associated with bystander programming may be maintained into early adulthood.