<![CDATA[Type 2 diabetes mellitus (T2DM) requires effective self-management to prevent complications, yet sustaining healthy behaviors remains challenging. The Health Belief Model (HBM) is widely used to promote behavioral change through educational interventions. This systematic review evaluated the effectiveness of group-based HBM interventions in improving health behaviors among adults with T2DM. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. PubMed, Scopus, and Google Scholar were searched for studies published between January 2021 and June 2026. Eligible studies included randomized controlled trials, quasi-experimental studies, controlled trials, and pretest–posttest intervention studies involving adults with T2DM receiving group-based HBM interventions. Study quality was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist. Of the 255 articles identified, four studies met the inclusion criteria. Group-based Health Belief Model (HBM) interventions consistently improved self-care, medication adherence, dietary compliance, physical activity, blood glucose monitoring, self-efficacy, perceived susceptibility, and perceived benefits while reducing perceived barriers. However, improvements in glycated hemoglobin (HbA1c) were inconsistent across studies. Group-based HBM interventions effectively improve health behaviors in adults with T2DM and may strengthen Diabetes Self-Management Education (DSME). Further large-scale randomized controlled trials with longer follow-up are needed to confirm their long-term effects on glycemic control and diabetes-related outcomes.]]>
