Vaccination programmes around the world have faced challenges due to low or decreasing public confidence in vaccination. Human Papillomavirus (HPV) vaccination, administered to adolescents, is particularly mistrusted, reflected in low uptake rates in countries such as France. While a range of psychosocial factors have been found to influence vaccine confidence among adults, less evidence exists for adolescents. A qualitative research was conducted as part of this PhD to identify and characterise psychosocial factors influencing adolescent girls’ decision-making for HPV vaccination in France. Between October 2018 and March 2019, 24 semi-structured interviews were conducted with 15-16-year-old adolescent girls and 21 with their mothers in Paris. Additionally, 12 girls took part in two focus groups. A codebook approach to thematic analysis based on deductive and inductive coding was used to analyse the transcripts. Adolescents were found to make decisions based on vaccine risks and benefits’ perceptions and to be influenced by information, group dynamics, trust, and contextual factors. While these factors are similar to the ones influencing mothers, differences in the type of influence were identified. Adolescents, for example, reported more positive and beneficial views and emotions towards HPV vaccination or expressed more trust in vaccines and health authorities than mothers. Maturity was also found to influence adolescents’ involvement in decisions and their decision-making process. Interestingly, the conflicting and sometimes anxiety-inducing vaccination environment led to adolescents showing more signs of rational rather than impulsive or emotional decision-making than mothers. These findings are summarised in an innovative model of adolescent vaccination decision-making, which can be helpful for the development of strategies aimed at increasing confidence in adolescent vaccines, especially in the recent context of the COVID-19 pandemic in which adolescents have been more engaged and empowered to take control over their own health.