The unique electronic configuration and structural properties of ceria make ceria‐based nanomaterials such as morphology‐dependent ceria nanocrystals, rare earth‐doped ceria‐zirconia solid solutions and noble metal‐ceria nanocomposites effective promoters in three‐way catalysts for low‐temperature water‐gas‐shift reaction, preferential oxidation of traces of CO, the treatment of toxic auto‐mobile exhaust, etc. The activities of nanoceria catalysts can be determined by their morphologies, oxygen vacancies, interfacial structures and the type of exposed crystal surfaces, as well as the synergistic effect exhibited by nanocomposites. In this review, the state‐of‐the‐art developments in the well‐controlled synthesis of ceria‐based nanocatalysts and their applications in both environmental and energy fields is summarized. The involved reaction mechanisms are also briefly introduced, and eventually an outlook in the design of novel nanoceria catalysts for valuable energy applications is addressed.