The purpose of this study was to construct and examine the nature of relationships among serious leisure, social capital, and recreation specialization. A total of 250 usable structured questionnaires were collected from participants of university and college guitar clubs in Taichung City, Taiwan using purposive sampling. Data was analyzed by confirmatory factor analysis (CFA) and structural equation modeling (SEM). The results indicate the following: (1) serious leisure has a positive and significant effect on recreation specialization; (2) serious leisure has a positive and significant effect on social capital; (3) social capital has a positive and significant effect on recreation specialization; (4) social capital partially moderates the relationship between serious leisure and recreation specialization. Managerial implications are discussed and future research directions are proposed in this study as well.