There are no approved drugs for the treatment of non-alcoholic fatty liver disease (NAFLD). However, many randomized controlled trials (RCT) have examined the effect of anti-hyperglycaemic agents on NAFLD in patients with and without type 2 diabetes mellitus (T2DM), since both T2DM and insulin resistance are closely linked to this burdensome liver disease. We systematically searched publication databases using predefined keywords to identify head-to-head or placebo-controlled RCTs (published until September 30, 2019) of NAFLD individuals testing the efficacy of anti-hyperglycaemic drugs to specifically treat NAFLD or non-alcoholic steatohepatitis (NASH). Outcomes of interest included changes in serum liver enzyme levels, liver fat, liver fibrosis, or histologic resolution of NASH. We included 29 RCTs involving a total of 2,617 individuals (∼45% had T2DM) that have used metformin (n=6 studies), glitazones (n=8 studies), glucagon-like peptide-1 receptor agonists (n=6 studies), dipeptidyl peptidase-4 inhibitors (n=4 studies) or sodium-glucose cotransporter-2 inhibitors (n=7 studies) to treat NAFLD. Although most anti-hyperglycaemic drugs improved serum liver enzyme levels, only glitazones (especially pioglitazone) and liraglutide showed an improvement of histologic features of NAFLD, with a mild beneficial effect also on liver fibrosis for pioglitazone only. RCT evidence supports the efficacy of some anti-hyperglycaemic agents (especially pioglitazone) in patients with NAFLD or NASH, though weight gain with pioglitazone may warrant caution. Further well-designed RCTs are needed to better characterize the efficacy and safety of monotherapy and combination therapy with anti-hyperglycaemic agents in patients with NAFLD.