We report monoaxial electrospinning and self‐assembly characterization of poly(3‐hexylthiophene)/[6,6]‐phenyl‐C61‐butyric acid methyl ester (P3HT/PCBM) nanofibers. Nanofibers were directly compared to films (as made and annealed) to understand the effects of extensional forces and high evaporation rate inherent to electrospinning on nanoscale structure. X‐ray scattering shows electrospinning can achieve improved crystallinity and reduced length scale of P3HT and PCBM phases. Due to extensional flow, co‐continuous phases form along the fiber axis, as evident in transmission electron microscopy. To our knowledge, this is the first study to investigate monoaxially‐spun, pure P3HT/PCBM nanofibers, a facile processing method with the potential to transform the field of wearable photovoltaics.