Aims/Introduction: Psychological therapies have showed benefits for both glycemic control and psychological outcomes in people with diabetes. However, the effects of mindfulness-based intervention (MBI) on glycemic control and psychological outcomes are inconsistent across studies, and the evidence for MBI has not been summarized. We aimed to identify the effects of MBI on glycemic control and psychological outcomes in people with diabetes by carrying out a systematic review and meta-analysis. Materials and Methods: Six databases (Pubmed, Embase, CINAHL, Cochrane, Web of science and PsycINFO) were searched from inception to October 2019. Randomized controlled trials of MBI for people with type 1 and type 2 diabetes were included. Two authors independently extracted relevant data and assessed the risk of bias, with a third reviewer as arbitrator. Subgroup analyses and sensitivity analyses were also carried out. Results: Eight studies with 841 participants met the eligibility criteria. Meta-analysis showed that MBI can slightly improve glycosylated hemoglobin (HbA1c; −0.25%, 95% confidence interval [CI] −0.43 to −0.07) and diabetes-related distress (−5.81, 95% CI −10.10 to −1.52) contribute to a moderate effect size in reducing depression (standardized mean difference −0.56, 95% CI −0.82 to −0.30) and stress (standardized mean difference −0.53, CI −0.75 to −0.31). Subgroup analyses showed greater HbA1c reductions in subgroups with baseline HbA1c levels <8% and follow-up duration >6 months. Mixed effects were observed for anxiety. Conclusions: MBI appears to have benefits on HbA1c, depression, stress and diabetes-related distress in people with diabetes. More rigorous studies with longer follow-up duration are warranted to establish the full potential of MBI.