Introduction: This study aimed to determine the effectiveness of educational intervention based on a self-efficacy model and its effect on two constructs of self-efficacy and outcome expectations in order to promote self-care and glycemic control in patients with type II diabetes. Materials and Methods: This pretest-posttest with randomized control group study was conducted on 80 patients with type-2 diabetes. These patients were selected based on inclusion criteria and were randomly divided into the intervention and control  groups (n=40 each). The intervention group attended six sessions of group and face-to-face consultation sessions focused on self-efficacy and outcome expectation strategies. Data were collected through laboratory tests and questionnaires before and three and six months after the intervention. Data were analyzed using SPSS software version 21and One-Way ANOVA and ANOVA for repeated measurestests. Result: Three months after the intervention a significant increase occurred in intervention groupsin self-efficacy, outcome expectations and self-care and these changes were statistically significant at 6 months after the intervention. Six months after the intervention a significant decrease in HbA1c was observed.After the intervention diet, physical activity and foot care improved significantly. No significant improvement occurred in self-monitoring of blood glucose and medication adherence. Conclusion: The results of this study suggest that educational interventions based on the self-efficacy model in six months is beneficial for diabetic patients. It seems that implementing these educational strategies can be effective for patients with diabetes and are recommended to be used in their education for metabolic control.