The use of nanocomposites to develop Carbon Nanotubes-based flexible sensors has been a cornerstone in recent years. Certain attributes, like enhanced mechanical integrity and easy customization of the prototypes, create an opportunity to use a wide range of polymer matrices to integrate with different physiochemical forms of Carbon Nanotubes. This chapter highlights some of the significant examples of nanocomposite-based flexible sensors that have been developed using Carbon Nanotubes, and subsequently, used for electrochemical and strain-sensing applications. The experiments have been shown to validate the ability of the Carbon Nanotubes to amalgamate with both insulative and conductive polymers, in the likes of polydimethylsiloxane and poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate, respectively. Each of the examples showcases the fabrication process, performance in terms of analytical parameters and their chosen application.