Introduction: Human papillomavirus vaccine school entry requirements may be an opportunity to improve the low rates of human papillomavirus vaccination among adolescents. This study evaluates changes in provider-verified human papillomavirus vaccine uptake by age 13 years for adolescents in Rhode Island compared with all other states from 2011 to 2017. Methods: The National Immunization Survey-Teen 2011–2017, a population-based cross-sectional survey, was analyzed in 2019. The survey included telephone interviews and provider-verified reports of vaccination among U.S. adolescents aged 13–17 years. The sample was subset to participants with provider-verified human papillomavirus vaccination reports (n=145,153). A difference-in-differences approach evaluated the Rhode Island human papillomavirus vaccination school entry requirement enacted in 2015. The main outcome was provider-verified human papillomavirus vaccine uptake by age 13 years. Results: Compared with boys in other states, boys in Rhode Island had an increase of 14 percentage points in the probability of uptake of human papillomavirus vaccination by age 13 years (β=0.139, 95% CI=0.073, 0.205). No such differences were observed on comparing girls in Rhode Island with girls in other states (β=0.009, 95% CI= −0.068, 0.086). Conclusions: The Rhode Island school entry requirement for human papillomavirus vaccination improved rates of vaccine uptake among boys and may be a useful option for improving human papillomavirus vaccination nationally.