Objective: Health care provider recommendation is a key determinant of human papillomavirus (HPV) vaccination. We developed an online training program for providers that addressed vaccine guidelines, hesitancy to strongly recommend the vaccine, and reluctance to discuss HPV infection as a sexually transmitted infection. Design: Single-group evaluation with 3 waves. Providers completed a 29-item electronic survey with closed and open-ended response options after course completion. Setting: Pediatric and family medicine practices in North Carolina. Participants: Prescribing clinicians (MD, DO, family nurse practitioner, physician assistant) who serve preteens aged 11 to 12 years. In wave 3, we expanded our communities to include nursing and medical staff. Intervention: An asynchronous online course to promote preteen HPV vaccination. Topics included HPV epidemiology, vaccine recommendations from the Advisory Committee on Immunization Practices (ACIP), preteen-provider-parent communication, topics about hesitancy to seek vaccination, subjects related to sexual health, and practice-level strategies to increase vaccination rates. The course, approved for 12 CME and CNE credits, was live for 4 weeks and available on-demand for 3 additional months. Main Outcome Measures: Provider-reported change in vaccine communication, perceptions of course content in improving practice, and satisfaction with materials. Results: A total of 113 providers from 25 practices enrolled in the course and 69 (61%) completed an evaluation. Providers spent an average of 6.3 hours on the course and rated the CDC (Centers for Disease Control and Prevention)-ACIP Web site and multiple resources on hesitancy and communication about sexually transmitted infection vaccines most highly of all materials across the 3 waves. Almost all (96%) agreed the course will improve their practice. About half of all participants said they were either "much more likely" (28%) or "more likely" (19%) to recommend the vaccine after course participation. Conclusions: An online format offers a highly adaptable and acceptable educational tool that promotes interpersonal communication and practice-related changes known to improve providers' vaccine uptake by their patients.