Background The high prevalence of overweight or obesity in patients with type 2 diabetes (T2DM) is strongly associated with impaired quality of life and an increased risk of long-term complications. Poor glycemic control remains a fundamental clinical challenge in this population. Although resistance training (RT) is an effective intervention for improving HbA1c levels, the optimal dosing parameters (e.g., frequency, intensity, volume) have not been systematically established. Therefore, this meta-analysis aimed to investigate the dose-response relationships between various RT regimens and HbA1c reduction in overweight or obese individuals with T2DM. Methods This systematic review and network meta-analysis, conducted by searching PubMed, Embase, and the Cochrane Library, included randomized controlled trials on resistance training in patients with T2DM who were overweight or obese, conducted from the inception of the databases through January 19, 2026. Comprehensive data extraction covered training dose, resistance training protocols, participants’ demographic characteristics, and study duration. Results A total of 10 studies involving 633 participants (mean age: 60.03 ± 7.77 years; mean BMI: 30.69 ± 6.64; Male: 32.7%) were included in this study. The results of our network meta-analysis showed that resistance training variables (e.g., frequency, intensity, period, and training volume) were effective in improving HbA1c in overweight or obese patients with T2DM. Among them, the effective dose range for frequency of resistance training was 3 times/week, resistance training intensity was 30-62%, resistance training period was 17–23 weeks, resistance training time was 45 minutes per session, resistance training exercises was 10 exercises per set, resistance training repetitions was 13–18 reps, resistance training sets was 2–4 sets, resistance training volume was 1000–2100 reps per week. the analysis suggested a potential optimum around of resistance training to improve HbA1c in overweight or obese patients with T2DM is 3 times/week (MD=-0.35, 95% CrI [-0.62, -0.08]), 44% 1RM (MD=-0.41, 95% CrI [-0.74, -0.08]), 23 weeks (MD = −0.35, 95% CrI [−0.68, −0.02]), 45min (MD = −0.32, 95% CrI [−0.62, −0.01]), 10 exercises (MD = −0.32, 95% CrI [−0.63, −0.01]), 18 reps (MD=-0.38; 95% CrI [-0.74, -0.02]), 3 sets (MD=−0.36, 95% CrI [−0.63, −0.10]), 1,500 reps/week (MD = −0.51, 95% CrI [−0.86, −0.15]). Conclusion Resistance training effectively improvesHbA1c in overweight or obese patients with T2DM. A recommended 23-week program includes 3 sessions per week at 44% 1RM, 45min per session, featuring 10 exercises per set, 3 sets, and 18 repetitions per exercise, totaling up to 1500 reps weekly. Systematic Review Registration https://www.crd.york.ac.uk/prospero/ , identifier CRD420261341070.