OBJECTIVE: To illustrate an evidence-, theory- and person-based approach to codesign the COMMUNICATE films that support parental decision-making about the human papillomavirus (HPV) vaccine for their teenagers. DESIGN: Codesign study. SETTING: Localities covered by two immunisation teams in London and the south-west of England. METHODS: The intervention planning phase involved combining evidence from a literature review with qualitative interview data to identify barriers and facilitators to HPV vaccine uptake, as well as design features that should be incorporated within the COMMUNICATE films. The intervention development phase involved identifying guiding principles for the COMMUNICATE films, mapping behaviour change techniques onto the behaviour change wheel and codesigning the COMMUNICATE films. Feedback from users informed modifications to maximise acceptability and feasibility and to support behaviour change. RESULTS: The primary and secondary evidence highlighted important content to include within the COMMUNICATE films: emphasise the benefits of the HPV vaccine, provide transparent information about the safety profile and side effects and emphasise the universality and commonality of HPV infection. A series of scripts were used to guide 4 film shoots to create the content in multiple community languages with 16 participants, including vaccine-hesitant, ethnically diverse parents and professionals. Overall, participants were positive about the films. Potential messengers and ways the films could be distributed, identified by parents, include local social media networks or text messages from general practices. The need for information about the HPV vaccine to be shared by schools ahead of consent being sought was also raised. CONCLUSIONS: By using an integrated approach to intervention development, this study has begun to address the need for an intervention to support vaccine-hesitant, ethnically diverse parents' decision-making about the HPV vaccination programme. A future study to codesign, implement and evaluate a communication strategy for the COMMUNICATE films is planned.