Background and aim: Metabolic dysfunction associated fatty liver disease (MAFLD) affects around one third of the world population. Within the MAFLD population, 19.2% are lean. Low serum vitamin D concentrations were reported to increase the risk of MAFLD. This study aimed to explore the association between serum vitamin D concentration and MAFLD. Methods: This cross-sectional study was conducted on 50 Egyptian patients with lean MAFLD (BMI>25 kg/m2) (Gl) and another group (G ll) including 50 consecutive overweight/obese patients with MAFLD (BMI 20 ng/ml) was predominant in G II (70% vs 58.0% in GI) while insufficiency (level: 20-30 ng/ml) was more common in GI (34% vs 26%). Sufficient vitamin D (level