3D MoO₃/PANI hybrid nanosheet networks were fabricated via hydrothermal, freeze-drying and electropolymerization methods. The structure, morphology, optical and electrochemical properties of the hybrid material were characterized using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical measurements. It was found that the conductivity of the 3D MoO₃ nanosheet networks was enormously enhanced by introducing PANI. The 3D MoO₃/PANI hybrid nanosheet networks show a complementary dual-electrochromic effect (ranging from light yellow to purple then dark blue), fast switching speed of bleached and colored states (0.9 and 1.0 s, respectively), superior coloration efficiency and better cycling stability. The results demonstrate that optical and electrochemical properties of 3D MoO₃/PANI hybrid nanosheet networks were improved compared to those of 3D MoO₃ nanosheet networks. The unique inorganic–organic hybrid nanosheet networks can be used as effective electrode materials in the optical–electrochemical field.