Hollow metal oxide nanospheres, such as niobium pentoxide, cerium oxide, and vanadia, have been successfully synthesized, for the first time, by templating a polymeric micelle of poly(styrene-b-2-vinyl-1-methylpyridinium iodide-b-ethylene oxide) (PS-PVMP-PEO). PS-PVMP-PEO forms a micelle with a PS core, a PVMP shell, and a PEO corona in aqueous solutions. The significance of the present method is that each block of the copolymer has its unique function in the synthesis of hollow metal oxide nanospheres; the PS core plays the role of a template of the cavity, while the cationic PVMP shell works as a reservoir and nanoreactor for the precursors of the metal oxides and the PEO corona stabilizes the polymer/inorganic hybrid to prevent secondary aggregate formation.