Background: Although receiving the HPV vaccine can help to prevent the development of cancer and HPV-related diseases, many individuals are not vaccinated in adolescence. Purpose: To examine knowledge about changes to the FDA's approval of the HPV vaccine for adults ages 26-45 years and to utilize the Integrated Behavioral Model (IBM) constructs to understand the relationship between beliefs and HPV vaccine intention. Methods: An online survey was used to examine HPV vaccine-related beliefs, knowledge, and uptake among a sample of 421 U.S. adults 18-45 years old in April 2019. Results: Perceived norms, perceived control, sex, and provider recommendation were significantly related to vaccine intention. Perceived norms, age, and healthcare provider recommendation were significantly related to receiving the full dose of the vaccine. Fewer than half of the participants indicated having at least one dose of the HPV vaccine or having had a provider recommend the vaccine. Less than 4% knew the vaccine had been approved by the FDA for up to 45 years old. Discussion: Results highlight the importance of social norms and patient education on HPV vaccine uptake and intention. Translation to Health Education Practice: Findings can inform future interventions and instrument development