Thailand has one of the world’s highest prevalence of cervical cancer, mainly caused by the human papillomavirus (HPV). HPV infections can successfully be prevented by vaccination, which is available at a cost but not yet implemented in the national vaccination program. Parents play a critical role in deciding whether to vaccinate their child against HPV. Thus, the aim was to examine the association between parents’ knowledge, beliefs, and acceptance of the HPV vaccination for their daughters, considering their socio-demographics and religious beliefs. A cross-sectional design was used among three schools in Thailand: Nakorn Phatom province (suburban) and Bangkok (urban). Parents of 9–12-year-old daughters completed the questionnaires, guided by the Health Belief Model. In total, 359 parents completed the questionnaires; of those, 301 were included in the final analyses. The ordinary least squares (OLS) regression analysis showed that background knowledge of HPV and the HPV vaccine was positively related to knowledge of HPV and cervical cancer. For beliefs, knowledge was positively associated with susceptibility (i.e., parents’ perceived risk of an HPV infection/ related disease), severity, and benefit. However, knowledge was not significantly related to barriers. For acceptance, higher susceptibility and benefit were related to higher acceptance, and greater knowledge was associated with higher acceptance. Thus, we found associations between parents’ knowledge, beliefs, and acceptance of the HPV vaccination for their daughters, considering their socio-demographics and religious beliefs. Parents, who reported religion as important, as opposed to those who did not, were more favorable toward the HPV vaccination. Four out of ten mothers had never undergone a cervical cancer screening, but most had accepted previous childhood vaccinations for their daughters. The overall acceptance of the vaccine was high, and we believe our results are promising for future implementation of the HPV vaccination in the national childhood vaccination program in Thailand.