Transition metal oxide nanotubes such as niobium have attracted wide scientific attention due to their unique properties such as high ionic mobility and large specific surface area. This study investigates the capacitive behavior of nanotubular niobium oxide obtained under extremely mild anodization conditions, aiming its application in supercapacitors. The nanotubular niobium oxide was obtained by potentiostatic anodization at 90 V at room temperature, in a glycerol electrolyte containing 0.4 M NH 4 F and 0.9% H 2 O. Field Emission Gun Scanning Electron Microscopy analysis (FEG-SEM) was employed to perform morphological characterization. The capacitive behavior of the obtained material was investigated by cyclic voltammetry and galvanostatic charge/discharge in a three-electrode system. The neutral aqueous electrolyte used was 1 M Na 2 SO 4 , in a potential window from −0.2 to −1.2 V vs. Ag/AgCl and 1 M H 2 SO 4 as an acid aqueous electrolyte in a potential window from −0.25 to −0.75 V vs Ag/AgCl. The FEG-SEM images revealed the presence of a self-organized highly ordered nanotubular niobium oxide layer on niobium substrate. Appreciable capacitance values of 20 mF cm −2 and 103 mF cm −2 were achieved in Na 2 SO 4 and H 2 SO 4 electrolytes, respectively. This great capacitive response can be associated with a large surface area achieved through the nanostructured oxide layer as well as the morphology of vertically aligned nanotubes that promote a directional ions transport, which, consequently, improves the capacitive performance. Besides, the results showed a superior performance, in terms of capacitance modulus and stability, for nanotubular niobium oxide in H 2 SO 4 electrolytes. The results obtained in this study highlight the great potential of the self-organized highly ordered nanotubular niobium oxide for application as a supercapacitor electrode.