Mesoporous CuO-NiO micropolyhedrons were fabricated via a facile, environmentally friendly, and scalable synthetic route for high-performance supercapacitors. The morphology and structure of CuO-NiO composites can be well tailored by tuning the molar ratio of Cu to Ni and processing temperature. The CuO-NiO micropolyhedrons were used as an electrode in a supercapacitor. The specific capacitance in a three electrode system was 370 F g−1 at a current density of 2 mA cm−2 with good capacitance retention of 84% after 500 cycles, which outperforms other CuO nanostructure-based supercapacitors. The remarkable performance of the resultant mesoporous CuO-NiO micropolyhedron-based supercapacitor was attributed to the unique mesoporous structure and a rational composition of the CuO/NiO constituents.