In this study, I explored the mediating role of person-job fit in the relationship between job autonomy and job engagement and proposed perceived supervisor support as an important moderator of the above mediated relationship. The survey data were collected from 385 full-time employees of two private firms operating in the service sector using the survey technique. SPSS 22, AMOS 22 and Process Macro (for SPSS) statistical programs were used to analyze the data. The results of the analysis indicated that the person-job fit has a mediating effect on the relationship between job autonomy and job engagement, and perceived supervisor support has a moderating effect in this relationship. In other words, the indirect effect of job autonomy on job engagement (through person-job fit) is strong when perceived supervisor support is high and weak when perceived supervisor support is low. The theoretical and practical effects of the results are discussed and suggestions are made for future studies and managers.