BACKGROUND/OBJECTIVES: Dietary quality plays a crucial role in maintaining liver function. In this study, we examined sex differences in the association between dietary quality and elevated liver enzyme levels in Korean adults. METHODS: This study included a nationwide sample of 15,997 males and 22,300 females in South Korea. Dietary assessment was performed using the Korean Healthy Eating Index (KHEI), an evidence-based dietary quality index that quantitatively reflects adherence to Korean dietary guidelines (range 0-100). Serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured, with individuals classified as having elevated AST or ALT levels when values were ≥40 IU/L or ≥35 IU/L, respectively. Logistic regression analysis was performed to examine the association between the KHEI and elevated AST or ALT levels stratified by sex. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined. RESULTS: Among the males, a 10-point increase in the KHEI score was inversely associated with the likelihood of having elevated AST (OR: 0.90; 95% CI: 0.85-0.96) and ALT (OR: 0.96; 95% CI: 0.92-1.00) levels, respectively. Among the females, there was no clear association between the KHEI and elevated AST (OR: 0.98; 95% CI: 0.91-1.05) or ALT (OR: 1.00; 95% CI: 0.95-1.05) levels. CONCLUSION: Further research is warranted to elucidate the underlying mechanisms of the observed sex-specific associations and guide the development of targeted dietary interventions for liver health in males and females.