Addressing numerous calls for future research on understanding the theoretical mechanisms that explain the relationship between organizational citizenship behaviors (OCBs) and job performance, this study focused on how an employee's relationships with coworkers mediate the relationship between his or her OCBs and his or her job performance. It also looked at how task autonomy might moderate this mediated relationship. The results of an empirical study involving 364 jewelry designers, 310 coworkers, and 284 supervisors indicated that coworker relations mediated the relationship between OCBs and job performance. In addition, task autonomy positively moderated both paths of this mediated relationship. Finally, these results hold for OCBs that are targeted at individuals but not for OCBs that are targeted toward organizations. (Contains 5 tables and 1 footnote.)