Intervention <p>Uptake of the HPV vaccine in Alberta, Canada, remains below the 90% immunization targets. Under Alberta’s expanded HPV vaccine policy, adults aged 18–26 are eligible for no-cost HPV immunization. This study describes a 2023 HPV vaccine intervention targeting seven post-secondary institutions in the province.</p> Research question <p>How do tailored HPV vaccine-promoting messages, informed by the Extended Theory of Planned Behaviour and delivered using a social influencer approach, influence 18–26-year-old Albertan’s HPV vaccine-related intentions and uptake?</p> Methods <p>Collaborating with Alberta post-secondary institutions and a not-for-profit mobile vaccine clinic, two clusters of HPV vaccine clinics were offered for up to 4 days, preceded by up to 2 weeks of a targeted HPV vaccine promotion campaign. Campaign messages were developed using the Extended Theory of Planned Behaviour and disseminated through socially influential approaches: post-secondary institutional social media platforms and on-campus initiatives. Data were collected from views and interactions with messages. Each message contained links to information about the HPV vaccine and immunization appointment bookings for eligible 18–26-year-olds.</p> Results <p>The campaign received 21,405 social media views, 270 interactions via likes, saves, and shares. A total of 279 individuals booked an HPV vaccine appointment and 195 were immunized during the intervention; 69 individuals sought an HPV vaccine but were deemed ineligible due to policy-related age restrictions. Post-secondary institutions most disseminated campaign messages that focused on perceived risk and HPV-related attitudes.</p> Conclusion <p>Targeted HPV vaccine messaging, as well as no-cost convenient HPV vaccine access may improve HPV vaccine uptake among post-secondary students.</p>