Background: Parental reports are commonly used for adolescent HPV vaccination status but may be subjected to bias. Guided by the Socioecological Framework, our study explores potential multilevel factors influencing the inaccuracy of parental reports of adolescent HPV vaccination status. Methods: Data from parents of 19,683 adolescents with provider-verified data were analyzed using multilevel modeling. Correlates included adolescent characteristics, parent/household factors, number of providers seen, state-level median income, and state-level HPV vaccine policy. Outcomes included inaccuracy in reporting: vaccine initiation (≥1 dose), completion (3 doses), and number of doses. Results: 24% and 25% of parents reported initiation and completion inaccurately; 28% underreported and 11% over-reported number of doses. All adolescent characteristics, parent/household factors, and number of healthcare providers seen were associated with the outcomes. Of note, compared to parents of White adolescents, parents of racial/ethnic minority adolescents were more likely to inaccurately report all outcomes (aOR ranges from 1.43-1.76 for initiation, 1.45-1.75 for completion, 1.98-2.05 for under-reporting, and 1.17-1.41 for over-reporting).