Non-alcoholic fatty liver disease (NAFLD) is a considerable challenge to public health across the globe. Whole grain is highly recommended as an inseparable part of a healthy diet and has been proposed as an effective way to manage NAFLD. The objective in the present study was to evaluate the effects of whole-grain consumption on hepatic steatosis and liver enzymes as primary outcomes in patients with NAFLD. Over the 12 weeks of this open-label, randomised controlled clinical trial, 112 patients (mean age 43 (sd 8·7) years; BMI 32·2 (sd 4·3) kg/m2) were randomly assigned to two groups to receive dietary advice, either to obtain at least half of their cereal servings each day from whole-grain foods or from usual cereals. By the end of the study, the grades of NAFLD showed a significant decrease in the intervention group (P < 0·001). In addition, a significant reduction in serum concentration of alanine aminotransferase (P < 0·001), aspartate aminotransferase (P < 0·001), γ-glutamyltransferase (P = 0·009), systolic blood pressure (P = 0·004) and diastolic blood pressure (P = 0·008) was observed in the intervention group compared with the control group. After adjusting, however, no significant differences were found between the two groups in terms of lipid profile, glycaemic status and anthropometric measurements. Overall, our study demonstrated that consumption of whole grains for 12 weeks had beneficial effects on hepatic steatosis and liver enzymes concentrations in patients with NAFLD.