Histone deacetylases 3 (HDAC3) is a member of the histone deacetylases family. This family is associated with cellular physiological function, such as signal transduction, cell cycle, proliferation, apoptosis, and cardiac development. HDAC3 plays an important role in the progression of malignant tumors, especially in terms of proliferation, apoptosis, metastasis, angiogenesis, and anticancer drug resistance. This review discusses the basic elements of HDAC3 and the relationship between HDAC3 and malignant tumors.