The results showed that insulin resistance and hepatic steatosis were associated with increased ATF3 expression and decreased fatty acid oxidation via mitochondrial dysfunction, which were attenuated by in vivo ATF3 silencing, suggesting that ATF3 may be a useful biomarker for predicting the progression of NAFLD and the development of T2D, and a potential central strategy for preventing these diseases. Here, ATF3 is linked to fatty liver disease.