Purpose: The purposes of the study were to examine the longitudinal changes of team cohesion within a Sport Education season among female students and to identify facilitators and barriers underlying cohesion development. Method: A longitudinal, concurrent, mixed methods design was employed. Students from sixth to eighth grades (all girls; n = 55) in small teams (n = 15), and their physical education teacher, from one convenience private school in a southern U.S. state, participated in this study. All students completed the validated "Youth Sport Environment Questionnaire" across three time points. Regular field observations, focus group interviews with students, and individual interviews with student leaders and the physical education teacher were conducted to capture the facilitators and barriers. Results: No significant time effect was observed for team cohesion, but student leadership significantly moderated cohesion development from Time 2 to Time 3 and from Time 1 to Time 3, but not from Time 1 to Time 2. Qualitative data unraveled four facilitators and three barriers underlying cohesion development. Conclusion: The findings are informative for future Sport Education-based curricular and instructional practices to nurture team cohesion.