Objectives: We sought to determine the effect of group discussion-based education on the self-management capability of patients with type 2 diabetes in Iran. Methods: This randomized control trial was conducted on 90 patients with type 2 diabetes. Participants were allocated randomly into one of two groups; intervention and control. The intervention group received the group discussion-based education while the control group received routine care only. The Lin's self-management questionnaire was completed at baseline and three months post-intervention. Results: Statistical analysis, including the use of independent t-test, identified that in comparison to the control group, significant increases were observed in the scores of self-organization (t =11.24, p < 0.001), self-adjustment (t = 7.53, p < 0.001), interaction with health experts (t = 7.31, p < 0.001), blood sugar self-monitoring (t = 6.42, p < 0.001), adherence to the proposed diet (t = 5.22, p < 0.001), and total self-management (t = 10.82, p < 0.001) in the intervention group. Conclusions: Sharing experiences through group discussions and receiving instructive feedback can improve the ability to self-manage diabetes.