||Thermoelectric materials are being investigated as a way to harvest electricity from waste heat. Nanocomposites are promising material class for bulk thermoelectric devices, but several challenges have to be overcome to make them suitable for practical applications. Nanostructure engineering is more effective than bulk material in enhancing thermoelectric figure of merit through phonon scattering at grain boundaries and interfaces. In this study, we prepared a series of thermoelectric nanofibers based on polyacrylonitrile (PAN) and transition metal oxide (NaCo2O4) precursors via sol-gel-based electrospinning and following calcination at different temperatures. The electrical conductivity, thermal conductivity, Seebeck coefficient, and power density of the thermoelectric nanofibers were investigated by considering the PAN/NaCo2O4 ratio, calcination temperatures, and morphological features.