Background: Limited human papillomavirus (HPV) related knowledge might be a barrier to future vaccine acceptance. From 2008-2010, PATH conducted an HPV vaccination demonstration project in partnership with the government immunization program in Vietnam, which included awareness campaigns prior to vaccination. Objective: To assess and compare knowledge and attitudes about cervical cancer and HPV vaccines between mothers and daughters, and whether knowledge was associated with vaccination status. Methods: We analyzed HPV-related knowledge and attitude data from mother-daughter paired responses to a cross-sectional household survey. After parents completed the survey, daughters were asked the same questions. We calculated the frequency of responses for each question and devised a scaled composite measure for knowledge. Results: Participants believed they had received enough information about cervical cancer and HPV vaccines and it was sufficient to make a decision about vaccination. Fifty percent of the participants knew HPV causes cervical cancer and 80% knew the HPV vaccine prevented cervical cancer. Mothers had more knowledge about cervical cancer and HPV infection (p<0.01), compared to daughters, who had more vaccine specific knowledge (p<0.01). However, the total mean knowledge score was similar for the groups. Girls not fully vaccinated had a lower mean knowledge score than fully vaccinated girls (p<0.001). Conclusions: Our results suggest that the purpose of the HPV vaccine was clearly messaged; however, some misconceptions about cervical cancer and HPV still exist. Limited knowledge about the magnitude of cervical cancer, HPV as a cause of cervical cancer, and HPV vaccines may have contributed to incomplete vaccination.