In the present study of 25,755 subjects aged equal to or more than 19 years from 2008 to 2014, serum levels of 25(OH)D > 21.40 ng/mL were inversely associated with unexplained elevation of liver enzymes (i.e., ALT > 30 IU/L for males and >19 IU/L for females, and GGT > 51 IU/L for males and >33 IU/L for females) and the NAFLD indices, when compared to subjects with 25(OH)D levels < 13.31 ng/mL. This evidence concerns the gene GPT and metabolic dysfunction-associated steatotic liver disease.