Carbon Nanotubes (CNTs), being one of the fundamental nanomaterials since the end of 20th century, has seen a huge demand in the academic and industrial sectors. They have been exponentially used to develop flexible sensors for various electrochemical and strain-sensing applications. The synthesis process of the CNTs-based sensors has been greatly improvised and optimized to increase their robustness and longevity for the chosen applications. This chapter highlights some of the primary printing techniques, including screen printing, laser ablation, inkjet printing and 3D printing, used to develop the CNTs-based flexible sensors. The chapter also explains some of the challenges that exist with the current sensors and their possible remedies.