Abstract Background This network meta-analysis aimed to compare the effects of bariatric surgery, novel glucose-lowering agents (SGLT2i, GLP1RA, DPP4i), and insulin for patients with type 2 diabetes mellitus (T2DM) and obesity. Methods Four databases were searched from inception to April 2023 to identify randomized controlled trials (RCTs) comparing bariatric surgery, SGLT2i, GLP1RA, DPP4i, insulin, and/or placebo/usual care among patients with T2DM and obesity in the achievement of HbA1c < 7.0 per cent within one year, and 12-month changes in HbA1c and body weight. Results A total of 376 eligible RCTs (149 824 patients) were analysed. Bariatric surgery had significantly higher rates of achieving HbA1c < 7.0 per cent than SGLT2i (RR = 2.46, 95 per cent c.i. = 1.28, 4.92), DPP4i (RR = 2.59, 95 per cent c.i. = 1.36, 5.13), insulin (RR = 2.27, 95 per cent c.i. = 1.18, 4.58) and placebo/usual care (RR = 4.02, 95 per cent c.i. = 2.13, 7.93), but had no statistically significant difference from GLP1RA (RR = 1.73, 95 per cent c.i. = 0.91, 3.44), regardless of oral (RR = 1.33, 95 per cent c.i. = 0.66, 2.79) or injectable (RR = 1.75, 95 per cent c.i. = 0.92, 3.45) administration. Significantly more GLP1RA patients achieved HbA1c < 7.0 per cent than other non-surgical treatments. Bariatric surgery had the greatest reductions in HbA1c (∼1 per cent more) and body weight (∼15 kg more) at 12 months. Among novel glucose-lowering medications, GLP1RA was associated with greater reductions in HbA1c than SGLT2i (−0.39 per cent, 95 per cent c.i. = −0.55, −0.22) and DPP4i (−0.51 per cent, 95 per cent c.i. = −0.64, −0.39) at 12 months, while GLP1RA (−1.74 kg, 95 per cent c.i. = −2.48, −1.01) and SGLT2i (−2.23 kg, 95 per cent c.i. = −3.07, −1.39) showed greater reductions in body weight than DPP4i at 12 months. Conclusion Bariatric surgery showed superiority in glycaemic control and weight management compared to non-surgical approaches. GLP1RA administered by oral or injectable form demonstrated reduced HbA1c and body weight at 12 months, and was preferable over other non-surgical treatments among patients with T2DM and obesity. PROSPERO registration no CRD42020201507