Glucagon-like peptide-1 (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors are both incretin-based therapies for type 2 diabetes (T2DM) but have distinct efficacy and side effect profiles. We thus performed a systematic review and meta-analysis to compare the effects of GLP-1 agonists to DPP-4 inhibitors on glycaemic control, weight and incidence of adverse events in adults with T2DM. We also sought to determine whether there was any additional effect in switching from DPP-4 inhibitor to GLP-1 agonist.