Objective: Influenza attack rates among college students are high. However, little is known about the determinants of students' flu vaccine adoption from their own perspectives. To fill this gap, this study aims to investigate barriers and facilitators to college students' flu vaccine adoption. Methods: A total of 545 students offered complete answers to an online survey. Thematic analysis was used for analyzing open-ended questions. Results: Students' flu vaccine adoption was hindered by their fear associated with the flu vaccine, lack of pertinent knowledge, perceived lack of necessity, negative social influence, and time constraints and convenience concerns. Students were motivated to adopt the flu vaccine for their interest in self-care, positive experience with the flu vaccine adoption, good flu vaccine habits, and recommendations from trusted sources. Conclusions: Understanding determinants of students' flu vaccine adoption provides the first step in developing tailored health interventions that may increase students' flu vaccine adoption rates.