Carbon nanotubes have extraordinary potential for the modification of reinforcements and matrices in fiber-reinforced polymer composites for enhanced mechanical properties. In this study, 12 fiber-reinforced polymer composites were produced with and without the addition of functionalized multi-wall carbon nanotubes using different stacking sequences of E-glass and carbon fabric reinforcements in simple and hybrid configurations. Carbon nanotubes were incorporated into the fiber-reinforced polymer components prior to composite fabrication by: (i) grafting on reinforcements, and (ii) matrix modification by carbon nanotubes. The grafting of carbon nanotubes exhibited a pronounced tensile behaviour with carbon-rich fiber-reinforced polymers, whereas carbon nanotube-modified matrix showed more enhanced flexural behaviour overall. Around 12% increase in tensile strength was observed when the carbon nanotubes were grafted on to the reinforcements compared to respective pristine composites, while around 70% increase in the flexural strength was noticed as compared to the respective pristine composties when carbon nanotube-modified matrix was used.