Today, municipality is counted as one of the largest social bodies. Its effectiveness requires appropriately organizational structure and employees’ commitment to increase performance. Managers should concentrate on attitude and behavior of service staff through cultural background, behavioral patterns, and managerial styles in order to obtain higher quality services. Thus, social capital results in achievement of members’ objectives by creating norms and mutual trust and it prepares a suitable ground for efficiency of human, financial, and economic capital. In this regard, this research investigates the impact of social capital on job performance by considering issues such as employees’ commitment and organizational citizenship behaviors. Statistical population includes 140 headquarters staff of Khoy Municipality. This research method is descriptive and correlational. Data were collected by questionnaire. In order to measure validity, the first and second order confirmatory factor analysis was used. To determine reliability, Cronbach’s alpha was used. Data were analyzed by Structural Equation Modeling. The results indicated positive impact of social capital on employees’ commitment, organizational citizenship behaviors, and job performance. However, the positive impact of employees’ commitment and organizational citizenship behaviors on their job performance was confirmed. As a result, it can be stated that improvement of processes related to employees’ commitment and organizational citizenship behaviors, affected by factors such as social capital, results in improvement of employees’ job performance.