The NAD(P)H:quinone oxidoreductase (NQO) family is a group of enzymes involved in cellular antioxidant defense, primarily including two members, NQO1 and NQO2. These enzymes are located in the cytoplasm and protect cells from oxidative stress damage by reducing quinone-like compounds and other electron acceptors. NQO1 is widely expressed in various tissues, especially in the liver, lungs, and kidneys, while the expression of NQO2 is more limited. The activity and expression levels of NQO family enzymes play important roles in cancer prevention, neuroprotection, and metabolic regulation. Mutations or abnormal expression of these genes are associated with various diseases, including cancer, neurodegenerative disorders, and cardiovascular diseases.