ABSTRACT Background: One of the main aspects of self-efficacy is a belief that one can affect his own life by applying control especially in facing stressful situations which commonly seen in military environments. Self-efficacy is a conditional variable which can be developed. Based on the result of previous researches, social support is one of the most important variables in increasing the self-efficacy of people, also, due to limited researches in this area, this study is done by the aim of investigating the relationship between self-efficacy and social support on the staffs of one of the military organization. Material and Methods: A total of 554 staff of one of the military organizations were selected trough multi-level categorical randomized cluster sampling method. The Sherre’s Self-efficacy Questionnaire, the Sametti’s Social Support Questionnaire and the Demographic Questionnaire were used to measure variables. Data was analyzed using descriptive statistical indices including mean and standard deviation and also inferential statistical method including Pearson correlation by SPSS16 software. Results: The results showed that there is a direct and significant relationship among all the social support's variables with self-efficacy of people (r=0/221, P=0.01). Social support is a mutual aid, conditions of military staffs, such as being away from the family for a long time and the lack of ability to arrange the strong social networks among them, are the reasons for the low correlation between two variables. Conclusion: These finding agree with previous studies and showed that The Social Support has role in predicting Self-efficacy of military staffs. It is recommended that managers support appropriate organizational bases for receiving social support and Increase self-efficacy for improving performance in military staffs.