Despite proven efficacy against cervical cancer, the HPV vaccination coverage in France – since 2019 recommended to 11- to 14-year-old girls and boys – is low with 32.7 % of 16-year-old girls fully vaccinated (2020). Based on an integrative model to understand vaccination behaviour, we aimed at understanding which psychological antecedents explain HPV vaccine acceptance among adolescents of both genders and their parents, and how the parental and child attitudes influence each other within families. This study includes the baseline data of a multi-component, multi-centre interventional research project in 64 middle schools in France (PrevHPV). Using an internet-based questionnaire and a confidential linkage code, the data are collected during December 2021-March 2022 among approximately 15 000 12- to 15-year-old adolescents (in classroom) and their parents (at home). In addition to socio-demographic data, the questionnaire includes information on: - Antecedents of vaccine hesitancy (VH) with both knowledge and attitude items based on a 7C-model; - Personal attitude and perception of attitudes in the participants’ environment (friends, family) about vaccination in general and vaccination against HPV in particular; - Vaccination status against HPV, intention to get vaccinated (based on the Prochaska et Di Clemente behaviour-change theory). Data collection is still ongoing and will end in March 2022. Results expected in June 2022 are as follows: - Attitudes mediate between knowledge and vaccine intention in adolescents and their parents; - Adolescents’ vaccine antecedents and intention are positively correlated with parental antecedents and intention.