The purpose of this study was to evaluate the monocyte to high-density lipoprotein (HDL) ratio (MHR) in patients with arteritic anterior ischaemic optic neuropathy (A-AION) and non-arteritic anterior ischaemic optic neuropathy (NA-AION). A total of 98 subjects were included in the study. Patients were divided into three groups: 16 patients with A-AION regarded as group one; 41 patients with NA-AION regarded as group two and 41 healthy subjects regarded as the control group. The MHR was calculated in all participants and compared between the patient and control groups. The mean age of subjects with A-AION, NA-AION and the control group were 75.9 ± 8.9 years, 67.1 ± 9.2 years, and 66.6 ± 6.7 years, respectively. Baseline clinical characteristics, such as diabetes mellitus and hypertension, were similar among groups. The mean MHR was significantly higher only in the A-AION group compared with the NA-AION and control group ( < .001), whereas there was no difference between NA-AION group and control group ( = .110). On receiver operating characteristic analysis, the area under the curve was 0.755, and the best cut- off value was 12.2 with a sensitivity of 72% and a specificity of 80%. An elevated MHR ratio is significantly associated with A-AION and MHR might be used to differentiate A-AION from NA-AION.