Objectives: To examine the relationship between Facebook(FB) use, relatedness and exercise motivation. Design: Two studies comprised a mixed-methods concurrent design. Study 1 was a cross-sectional quantitative assessment of the relationships between FB use, relatedness and exercise motivation. Study 2 explored qualitative perceptions of how FB influences exercise motivation. Method: Study 1: 311 undergraduate students completed a survey assessing FB use, exercise motivation and relatedness. Mediation analysis was conducted to examine relationships. Study 2: 19 participants took part in focus groups exploring experiences of exercise-related FB use and its perceived role in motivation. Results: Study 1: FB use was related to external and introjected regulation. Relatedness mediated the relationships between FB use, introjection, and autonomous forms of motivation. Study 2: Qualitative data suggested FB can either promote (through connection, positive social comparison) or discourage exercise (through disconnection, negative social comparison, health-negating features). Conclusion: FB use was related to external and introjected regulation. Positive relationships between FB and autonomous forms of motivation were mediated by relatedness, suggesting that interventions should focus on fostering feelings of connection with others. FB use that encourages relatedness with like-minded individuals has potential to promote autonomous motivation for exercise
