BackgroundDespite its effectiveness in preventing human papillomavirus (HPV) infection, the rate of uptake of the HPV vaccine is low in Vietnam. This study aimed to investigate barriers related to knowledge–attitude–practice (KAP) about the HPV vaccine and willingness to pay (WTP) for the vaccine among those using services in an urban vaccination clinic in Hanoi, Vietnam.Materials and methodsA cross-sectional study was conducted in a vaccination clinic of the Institute for Preventive Medicine and Public Health in Hanoi, Vietnam, from March to April 2016. KAP on the HPV vaccine was collected using a structured questionnaire. Double-bounded dichotomous-choice questions with open-ended questions were used to examine the WTP of respondents. Interval regression and stepwise logistic models were used to identify factors associated with WTP and the average amount that people would be willing to pay for the vaccine.ResultsOf 492 vaccination service users, 67.9%, 94.6%, and 12.3% of respondents were aware of the best age for HPV vaccination, its benefits, and the target group for vaccination, respectively. While the majority believed that the HPV vaccine was safe (92.8%) and effective (90.8%), and desired to be vaccinated (71.1%), only 31.8% of users were vaccinated. Most of the respondents were willing to pay for the HPV vaccine (86.6%), and willing to pay an average amount of US$49.3. Those aged 20–29 years and earning more than 22 million VND/month (very rich) were more likely to pay for the HPV vaccine than people aged <20 years and earning <7 million VND/month. Users who had attained more than a high-school education and heard about the HPV vaccine from doctors, nurses, or other health professionals tended to be willing to pay for the vaccine at a lower price than individuals with below secondary-level education and who had not heard about the vaccine from these health professionals.ConclusionSexual health education and financial assistance should be imparted alongside the HPV vaccination program.