Flexible supercapacitors have gained significant attention in recent times due to their many advantages such as high specific capacitance, lightweight, long lifespan, high energy density, high flexibility, and high-power density. These benefits make them ideal for various high-power applications in various industries. Copper oxide is particularly attractive as an electrode material because of its high theoretical specific capacitance, low cost, and eco-friendliness. Copper oxide is the most promising electrode material in energy storage systems among metal oxides due to its higher theoretical value of specific capacitance (1800 F/g). In the present study, the synthesis of a thin film of copper oxide on a flexible copper substrate through electrodeposition was carried out to produce a flexible and lightweight supercapacitor. The supercapacitor's performance was evaluated using cyclic voltammetry (CV) and galvanostatic charge–discharge analysis in a 1 M KOH electrolyte. The results showed that the copper oxide/copper-based supercapacitor had a large specific capacitance of 983.3 F/g and good performance even after 2200 cycles, with a capacity retention of 89.70%. The flexibility of the electrode was measured at various bending angles. The electrode showed a capacity retention of 87.5% after a 180° bending angle with a good coulombic efficiency of 79.15%. Hence, it could be a promising material for flexible supercapacitor electrodes. This demonstrates that copper oxide has great potential as a material for flexible supercapacitor electrodes. The newer applications for supercapacitors in industries such as wearable electronics, flexible displays, and energy harvesting systems can be explored.