Purpose: Physical activity (PA) has been shown to enhance quality of life (QOL) in older adults. Findings from these studies indicate that the relationship between PA and QOL is indirect and likely mediated by variables such as physical self-esteem, exercise self-efficacy, and affect. As PA varies greatly by age, the purpose of the current study is to extend this area of research to young adults and explore the complex relationship between PA and QOL in this target population. Methods: Data were collected via anonymous questionnaire from N = 590 undergraduate students. PA was assessed with the Godin Leisure Time Exercise Questionnaire, and QOL was assessed by the Satisfaction with Life Scale. Path analysis was used to test the relationship between PA and QOL, with mediators of exercise self-efficacy, physical self-esteem, and affect. Results: The PA model (RMSEA =.03, CFI =.99) accounted for 25 % of the variance in QOL. PA had positive direct effects on exercise self-efficacy (β =.28, P <.001), physical self-esteem (β =.10, P <.001), positive affect (β =.10, P <.05), and negative affect (β =.08, P <.05). Physical self-esteem was found to be the most powerful mediating variable on QOL (β =.30, P <.001), followed by positive affect (β =.27, P <.001) and negative affect (β =.14, P <.001). Conclusion: Physical self-esteem and, to a lesser extent, positive affect emerged as integral components in the link between PA and QOL. Findings suggest that health education programs designed to promote regular PA and increase physical self-esteem may be effective in improving QOL in young adults. © 2013 Springer Science+Business Media Dordrecht.