Research on the psychological drivers affecting employees’ work engagement is insignificant and scare. Psychological capital and ethical work climate are two important of those drivers that their impact on work engagement haven’t been investigated yet. The aim of this study is to investigate psychological capital and ethical work climate effect on employees’ service behavior by the mediating role of employees’ work engagement. The statistical population of this study includes 7000 employees of National Iranian Oil Product Distribution Company. 394 employees were the minimum sample which their data were collected from 397 employees by questionnaires. Confirmatory factor analysis and structural equation modeling were used to data analysis. Results showed that psychological capital and ethical work climate have direct and significant effect on employees’ work engagement. Also results showed their effects on service behavior. Finally, work engagement effect on employees’ service behavior was confirmed. Managers by improving employees’ work engagement can have significant effect on employees’ service performance and employees by providing high quality services can quarantine customers satisfaction, benefit for stakeholders and business survive. Managers and business owners especially in service sector can improve work engagement through creating and developing ethical climate in business and through emphasizing on workers psychological derivers by education.
