Cobalt oxide nanoparticles synthesized through simple microwave method are employed for supercapacitor studies. XRD analysis reveals the cubic phase of the synthesized nanoparticles. TEM image indicate uniform distribution of the nanoparticles. The blue shift of the band gap energy as obtained through optical absorption studies confirms the quantum confinement effect. PL spectra recorded at room temperature exhibit a broad emission in the UV/Violet region. Maximum specific capacitance of 519F/g was obtained from charge–discharge studies. After 1000 cycles of continuous charge–discharge cycles, only about 1.3% degradation in specific capacitance could be noticed. The microwave-assisted synthesized cobalt oxide nanoparticle appears to be a promising electrode material for supercapacitor application.