Human papillomavirus (HPV) infection is a leading cause of secondary malignancies in those who have survived cancer in childhood, especially cervical and anal tumors (HPV). However, HPV vaccination uptake is poor among young cancer survivors, despite its efficacy in preventing the infections that contribute to these cancers. Most cancer survivors who do not start the HPV vaccine do so because they have not been encouraged to do so by their healthcare professionals. Improving healthcare providers’ knowledge and ability to suggest the HPV vaccine confidently and lowering barriers faced by young people and their parents to receive the vaccine are 2 of the most effective strategies for improving HPV vaccine uptake in the general population. To boost HPV vaccination uptake among cancer survivors aged 9–17, this study will assess the efficacy and implementation of an evidence-based healthcare provider-focused intervention (HPV PROTECT) modified for pediatric oncology clinics. The research employs a mix of type 1 effectiveness and implementation strategies. Through a stepped-wedge cluster-randomized study in pediatric oncology clinics across multiple states, investigators will assess the efficacy of the HPV PROTECT intervention. The researchers used a mixed-methods approach to assess implementation (providers’ perceptions of the intervention’s feasibility, acceptability, and appropriateness in the pediatric oncology setting; providers’ fidelity to intervention components; and providers’ growth in their HPV vaccine-related knowledge and practices (e.g., recommendations for vaccination, elimination of barriers to vaccination). By evaluating the efficacy of an evidence-based provider-directed intervention adapted for the pediatric oncology setting, to increase HPV vaccine initiation in young cancer survivors receiving care in pediatric oncology clinics, and by collecting data on intervention delivery to inform future implementation efforts, this multisite trial will fill critical knowledge gaps related to the prevention of HPV-related malignancies in young cancer survivors. If HPV PROTECT was effective, it was widely disseminated for testing by the pediatric oncology community to enhance HPV vaccination uptake in cancer survivors and provide protection against HPV-related morbidities for this at-risk group.