Background: Diabetes mellitus (DM) has become a serious chronic disease.Self-management strategies help persons with DM make choices which will develop skills needed to reach their goal of blood glucose control and allow them to be successful in reaching goals.Objective: To examine the impact of self-management activities on HbA1c for persons with DM and to examine the impact of social support,self-efficacy and Buddhist values as moderators on the relationship between the self-management activities and HbA1c.Method: This study is a cross-sectional design.The sample included 401 Thai adults diagnosed with type 2 diabetes,aged 20-65 years old who had at least one HbA1c test in the last three months were recruited.Participants completed four questionnaires to measure self-management activities,as well as self-efficacy,Buddhist values and social support as moderating factors on self-management activities and HbA1 c,Results: The self-management activities were negatively associated (β =-2.05,p ≤ 0.001) with HbA1c.The Social support,self-efficacy and Buddhist values had a significant interaction effect between selfmanagement activities and HbA1c (β =-0.97,p ≤ 0.05,β =-0.18,p ≤ 0.05 and β =-2.76,p ≤ 0.001).Conclusion: The diabetes self-management activities were more strongly associated with HbA1c under conditions of high social support,self-efficacy and health beliefs with Buddhist values.Future interventions for T2DM self-management programs should incorporate mechanisms to measure and support these factors.