Introduction. Human papillomavirus (HPV) is the most common sexually transmitted infection (STI) worldwide. Despite recommendations forHPVvaccination of young women from health authorities, parental concerns were raised whether vaccination could induce unsafe sexual behaviour in young women. Therefore, the primary aim of this study was to investigate if HPV vaccination in healthcare seeking adult women in Luxembourg was associated with unsafe sexual behaviour. Methods. Seven hundred twenty-nine women (mean age D 22.5; range 18-43 years) were recruited either at Luxembourg family planning centres or at private gynaecology practices. All participants completed a questionnaire on vaccination status and sexual behaviour. Poisson and logistic regressions were used to study the association between sexual behaviour and vaccination status (N D 538). Both models were restricted to women younger than 26 years, since the first cohort being vaccinated would be 25 years old at the time of sampling. Assortativity of sexual mixing by age was also assessed for further transmission modelling for women < 30 years reporting age of last/current sexual partner (N D649). Women older than 29 years were excluded from the assortativity analysis due to restricted sample size. Results. In total, 386/538 (71.8%) of participants reported receiving HPV vaccine. Vaccination uptake significantly varied by nationality and was higher in Portuguese 112/142 (78.9%) and in Luxembourgish 224/313(71.6%) residents, and lower in residents of other nationalities 50/83 (60.2%) (p D 0.011). HPV vaccination was not associated with unsafe sexual behaviour such as shorter relationship duration with current or last sexual partner (odds ratio (OR)D1.05, 95% CI [0.94-1.16]), younger age of sexual debut (OR = 1.00, 95% CI [0.88-1.14]), increased number of lifetime sexual partners (OR = 0.95, 95% CI [0.87-1.03), higher age difference with sexual partner (OR = 1.01, 95% CI [0.95-1.08]), condom use (OR = 0.97, 95% CI [0.60-1.56]), nor with other factors like ...