© 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.Utilizing the grown carbon nanotubes (CNTs) on nanofibers having high surface area provides an ability to tailor mechanical, electrical and thermal performance in various applications such as lithium-sulfur batteries, laminated composites, and supercapacitors. In this study, growth of CNTs on curved polymeric nanofibrous substrates is conducted to address single-step CNTs synthesis on polybenzimidazole (PBI) nanofibers as an interlayer, which benefits from the synergetic effect of PBI nanofiber network and stiff and conductive CNTs. The growth of radially oriented CNTs on PBI nanofibrous substrates at 600 °C has successfully achieved by chemical vapor deposition method (CVD). Then, these interlayers are used for toughening in CF/PEEK laminated composites. The integration of CNTs-PBI interlayers into CF/PEEK laminated composites presented promising results under flexural loadings.