Objective: To explore the effects and dose–response relationship of Tai Chi for type 2 diabetes mellitus (T2DM) and to evaluate the methodological quality of the included trials and evidence quality of the outcomes. Methods: Nine major English and Chinese databases were searched for randomized controlled trials of Tai Chi for T2DM from inception to December 2021. The effects and dose–response relationships were assessed with a meta-analysis and meta-regression using Stata.16. The methodological quality of the included studies was assessed using the risk of bias tool. The evidence quality of the outcomes was assessed using the GRADE tool. Results: A total of 24 studies with 1314 patients were included. Compared with the usual care, Tai Chi improved HbA1c (MD = −0.80%, 95% CI [−1.05, −0.54], P