This study sought to identify barriers and facilitators to delivery of human papillomavirus (HPV) vaccination in schools. Four focus groups were conducted with 28 staff members, from four National Health Service school-aged vaccination (SAV) teams in London. Data were analyzed using thematic analysis. School engagement and support, and understanding and education about the vaccination (or conversely, a lack of) were identified as both barriers and facilitators. Limited school and team resources, fear of the vaccination, and poor consent form return were identified as barriers. Explanations for why some girls do not complete the vaccination series were provided. Individualizing approaches used to promote and encourage the vaccination was identified as a facilitating factor. Optimal delivery of the HPV vaccination program is dependent on school engagement and the allocation of time for SAV teams to promote vaccination uptake. Immunization program providers should work with schools to improve understanding and support of the HPV vaccination program.