Rates of human papillomavirus (HPV) vaccine series completion among adolescent Hispanic females in Texas in 2014 (~39%) lag behind the Healthy People 2020 goal (80%). This qualitative study identifies Hispanic mothers' salient behavioral, normative and control beliefs regarding having their adolescent daughters complete the vaccine series. Thirty-two mothers of girls (aged 11-17) that had received at least one dose of the HPV vaccine, completed in-depth interviews. Six girls had received one dose of the HPV vaccine, 10 girls had received two doses, and 16 girls had received all three doses. The questions elicited salient: (i) experiential and instrumental attitudes (behavioral beliefs); (ii) supporters and non-supporters (normative beliefs) and (iii) facilitators and barriers (control beliefs). Directed content analysis was employed to select the most salient beliefs. Mothers: (i) expressed salient positive feelings (e.g. good, secure, happy and satisfied); (ii) believed that completing the series resulted in positive effects (e.g. protection, prevention); (iii) believed that the main supporters were themselves, their daughter's father and doctor with some of their friends not supporting series completion and (iv) believed that vaccine affordability, information, transportation, ease of scheduling and keeping vaccination appointments and taking their daughter's immunization card to appointments were facilitators. This study represents the first step in building theory-based framework of vaccine series completion for this population. The beliefs identified provide guidance for health care providers and intervention developers.