Past researchers have found that motivating job characteristics can increase employee display of organizational citizenship behavior (OCB). In this study, the authors extended previous research by investigating the mediating process of job involvement in the relationship between job characteristics and OCB. The authors collected data from 323 employees and their supervisors from 7 companies in Taiwan. Results show that, through the mediating process of job involvement, the 3 job characteristics (i.e., task identity, task significance, and autonomy) positively influenced the display of an employee's OCB, whereas skill variety had a negative effect on OCB. The authors discuss implications of their findings, contributions, limitations, and future research directions.