Metabolic dysfunction-associated fatty liver disease (MAFLD) is often linked to overweight and obesity. However, a significant number of individuals with MAFLD are not obese, commonly referred to as lean MAFLD. This study aims to investigate the potential risk factors for fibrosis among lean individuals with MAFLD compared to those who are overweight or obese. The study included 7902 participants from the National Health and Nutrition Examination Survey (NHANES) data collected between 2017 and March 2020. MAFLD was defined in individuals with steatosis who were either overweight, diabetic, or lean and had at least two metabolic risk abnormalities. Demographic, anthropometric, and laboratory data, along with elastography results, were reported for each subject. Lean patients with MAFLD were significantly older (62.3 ± 13.8 years) compared to overweight or obese patients with MAFLD (51.7 ± 16.7 years; p < 0.001). Several factors were identified as predictors of significant fibrosis within the MAFLD population, including increasing age, BMI, ALT levels, alkaline phosphatase levels, lower platelet counts, lower HDL-cholesterol levels, and the presence of diabetes. In a multivariate logistic analysis of significant fibrosis (F > 2) in patients with obese MAFLD, female gender, diabetes, and hypertension were identified as risk factors. For lean individuals with MAFLD, older age, high AST levels, and lower platelet counts were found to be significant predictors of fibrosis. MAFLD among lean individuals is not a benign condition; those with metabolic dysfunction are at risk of developing fibrosis. The risk factors for fibrosis in these individuals may differ from those in their obese counterparts.