Non-alcoholic fatty liver disease (NAFLD) is a growing global health concern and is characterized by fat accumulation in the liver in the absence of significant alcohol consumption. However, current diagnostic tools, including liver biopsy and imaging techniques, have limitations in terms of accessibility, invasiveness, and sensitivity. Recently, microRNAs (miRNAs) have emerged as non-invasive biomarkers for the diagnosis of NAFLD. In this study, we investigated the expression of three microRNAs (miR-16, miR-10b, and miR-21) in patients with NAFLD across different disease stages compared with healthy subjects. First, miRNAs were extracted from serum samples collected from 34 healthy controls and 38 patients with NAFLD, including 20 with grade 1 and 18 with grade 2 of the disease. Subsequently, cDNA was synthesized from RNA, and miR-21, miR-16, and miR-10b expression was measured using RT-qPCR. The results revealed the downregulation of miR-16 in the early and advanced stages of NAFLD. The serum expression of miR-21 (p < 0 0.01) and miR-10b (p < 0.05) increased in the total NAFLD samples compared with the control group. Moreover, miR-10b expression was significantly higher in patients with stage 2 of NAFLD than in those with stage1 of NAFLD (p < 0.05), suggesting its potential as a biomarker to distinguish between the different grades of the disease. Our results revealed the clinical value of these miRNAs as non-invasive, sensitive, and stage-specific biomarkers for NAFLD. These findings suggest that the assessment of miR-16, miR-21, and miR-10b expression levels could serve as a potentially useful tool for the diagnosis of NAFLD presence and severity.