BACKGROUND: The English schools-based human papillomavirus (HPV) vaccination programme is routinely offered to all young people aged 12-13 years, to prevent cancers affecting the cervix, vulva, vagina, penis, anus and mouth. Lower uptake among some population groups has been identified, in part, because of unmet information needs among young people. To address these unmet needs we report intervention planning and development processes to co-produce an educational package about the HPV vaccine. METHODS: We used co-production research methodologies and the 'person-based approach' involving the following iterative stages: (i) collating and analysing primary and secondary evidence, including HPV vaccine communication materials, interviews and workshops; (ii) developing guiding principles; (iii) undertaking a behavioural analysis informed by the Behaviour Change Wheel and the Behaviour Change Technique taxonomy; (iv) development of a preliminary logic model; (v) co-production of resources, and; (vi) refinement of resources informed by feedback from young people and key informants. RESULTS: We co-produced EDUCATE, a theory-based educational package, that is designed to be delivered to young people prior to being offered the HPV vaccine to support uptake. Young people and key informants identified the following key issues to include as content: (i) HPV-related information; (ii) how vaccines work; (iii) safety and side-effects of the HPV vaccine; (iii) eligibility for the HPV vaccination programme, and; (iv) preparation of young people to receive the HPV vaccine. A manual for professionals (e.g. immunisation nurses, school staff) delivering the intervention and a PowerPoint presentation, interspersed with five short films, were co-produced with young people and key informants. Following feedback, the content of the EDUCATE package was refined to increase acceptability, engagement, and persuasiveness to the target users. CONCLUSION: Engagement with young people and key informants was integral to the development of our rigorously developed, theory-based intervention to address young people's information needs about the HPV vaccination programme. The acceptability and persuasiveness of the package has been maximised by working closely with young people and key informants to develop the content. An implementation study to examine how the EDUCATE package is implemented in practice and the impact on uptake of the HPV vaccination programme is underway.