Recently, entropy stabilized catalytic systems have been raised great concerns due to the urgent demand for functional materials aiming to realize chemical catalysis. As one of the significant groups, high entropy oxides (HEOs) with variable structure, controllable chemical composition, and rich functional properties have become the research hotspots. This review briefly introduces the advantages of HEOs in the catalytic system brought by their structural characteristics and fully summarizes recent applications of HEOs in thermal/electro/photo-catalysis and supports. Finally, the future prospects of HEOs in environmental catalysis, such as visible light catalysis, catalytic wet air oxidation (CWAO), and single-atom catalyst supports are proposed, which will provide a general direction for the development and breakthrough of HEOs in related fields. • The applications of HEOs in catalysis and support were summarized. • The active sites of HEOs in catalysis and support were analyzed. • The prospects of HEOs in environmental catalysis were provided.