Objective: We aimed to explore knowledge, attitudes, and beliefs about vaccines required for college-entry and vaccine-related behaviors among college students. Participants: Thirty-three full-time undergraduate students, [greater than or equal to] 18 years old, enrolled at public (2) and private (3) colleges and universities in metropolitan Philadelphia in fall 2016. Methods: We conducted semistructured interviews, which were double-coded with 5,015 comments overall and 99.3% intercoder reliability ([kappa] = 0.779) using NVivo 11 software. Results: Six key themes emerged: (1) low knowledge about vaccines and requirements; (2) mixed attitudes about required vs. recommended vaccines; (3) high trust in medical professionals; (4) low perceived risk for vaccine-preventable disease outbreaks; (5) substantial parental influence on students' decision-making; and (6) low utilization of Student Health Services. Conclusions: This study revealed lack of knowledge about and low prioritization of vaccination despite overall positive attitudes towards vaccines. Prematriculation education of college students is critical to increasing vaccine knowledge and use.