Nanostructured semiconducting materials show intriguing properties not possessed by their macroscopic counterparts. First of all they exhibit high surface area to volume ratio, which offers interesting possibilities in several applications, as the improved and increased solar light adsorption in photoelectrochemistry and photocatalysis. Low charge-carrier mobility and high charge recombination rates are the key limiting factors in solar energy conversion systems. New extraordinary opportunities arise by the exploitation of nanomaterials. Indeed, learning to fine tune the behavior of nanoscale semiconductors and to integrate them in real devices have become one the main topics in the energy-related fields. Significant work has been especially done demonstrating that innovative photovoltaic architectures, and well-performing photoelectrochemical systems can be designed by the proper integration of nanostructured semiconducting metal oxides. In this scenario nanofibers by electrospinning have attracted great interest, since they can be obtained by a relative simple and low-cost process, if compared to other technologies used for the fabrication of nanostructures. Moreover electrospinning offers several possibilities and strategies to design nanofiber-based nanostructures with different arrangement, well-controlled composition and morphology.