Diacylglycerol acyltransferase 2 (DGAT2) is one of two distinct DGAT enzymes that catalyze the last step in triacylglycerol (TG) synthesis. Findings from previous studies suggest that inhibition of DGAT2 is a promising strategy for the treatment of hepatic steatosis and insulin resistance. Here, we identified compound 122 as a potent and selective inhibitor of human DGAT2, which appeared to act competitively against oleoyl-CoA in vitro . The selective inhibition of DGAT2 was also confirmed by the reductions in enzymatic activity and de novo TG synthesis in DGAT2-overexpressing HEK293 cells and hepatic cells HepG2. Compound 122, as a newly identified inhibitor of DGAT2, will be useful for the research on DGAT2-related lipid metabolism as well as the development of therapeutic drug for several metabolic diseases.