Abstract Hollow calcium tungstate (CaWO4) nanospheres with well-controlled shape and size have been successfully synthesized for the first time by templating micelles of poly(styrene-b-acrylic acid-b-ethylene oxide) (PS-b-PAA-b-PEO). This polymer forms a micelle with a PS core, a PAA shell, and a PEO corona in aqueous solutions. Calcium chloride (CaCl2) and sodium tungstate (Na2WO4) were used as precursors of CaWO4. In the synthesis, the PS core acts as a template for cavities of the hollow particles, the PAA shell is beneficial for arresting calcium ions for further mineralizing, and the PEO corona stabilizes the CaWO4-polymer nanocomposite to prevent secondary aggregate formation. The hollow CaWO4 nanoparticles have a spherical shape with an outer diameter narrowly distributed at 22.7 ± 1.0 nm and a shell thickness at 6.7 ± 0.4 nm.