Electrospinning and spin-coating techniques were used for the fabrication of polyacrylonitrile/polyaniline/WO3 (PAN/PANI/WO3) nanocomposite nanofibers as a counter electrode of DSSCs. Scanning Electron Microscopy, Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, Cyclic Voltammetry and Electrochemical Impedance Spectroscopy were used for characterization of the fabricated nanofibers. Fabrication of bead-free and smooth nanofibers was confirmed and reduction of the average diameter of nanofibers by increasing in PANI content from 482 to 88 nm was clearly shown in SEM images. In the Spin-coating of WO3 nanoparticles on the surface of the PAN/PANI nanofibers, the lowest agglomeration was observed at 2 wt % of WO3. The results showed that the electrocatalytic activity of the mats is enhanced when PANI content in the electrospinning solution increases. The same positive effect was obtained by the presence of WO3 nanoparticles on the surface of the mats. The results of the photoelectric analysis indicated that these novel fibrous nanocomposites with the efficiency equal to 2.72 can be usable as a new catalyst for DSSCs counter electrodes.