Three-dimensional (3D) graphene oxide/polypyrrole (GO/PPy) composite electrodes have been fabricated via a one-step electrochemical co-deposition in an aqueous solution containing pyrrole monomer, GO and LiClO4. The concentration of GO in the solution plays an important role in controlling the morphologies of the as-deposited GO/PPy composites, and a relatively low concentration as 0.1 mg mL−1 is favorable for the formation of 3D interconnected structure. The unique 3D interconnected structure assures fast diffusion of electrolyte ions through the electrode. As a result, the GO/PPy composite electrode with a mass loading of 0.26 mg cm−2 exhibits the highest specific capacitance of 481.1 F g−1, while the electrode with a larger mass loading of 1.02 mg cm−2 delivers the best area capacitance of 387.6 mF cm−2, at a current density of 0.2 mA cm−2. Moreover, the GO/PPy composite electrodes exhibit good rate capability with capacitance retentions over 80% when the current density load increases from 0.2 to 10 mA cm−2. Both of the aqueous and solid-state supercapacitors based on GO/PPy composite electrodes show excellent capacitive properties with good cycling stability, indicating their suitability for applications in energy storage and management.