An investigation was carried out to characterize the tensile behavior of multiwalled carbon nanotube (MWCNT) modified epoxy nanocomposites in the glassy, viscoelastic, and rubbery regimes. 1 and 2 wt% MWCNT predispersed epoxy was used in this study. The cured samples were characterized using dynamic mechanical analysis for selection of different temperatures. The stress–strain behavior and toughness were determined in the temperature band of 25–140 °C. Addition of 1% CNT resulted in 16% improvement in the storage modulus at glassy state but 6% reduction in storage modulus was seen for 2% CNT-epoxy system. Tensile results showed that the strength and modulus have improved for 1% CNT-epoxy system. This study also revealed that for all the three systems, failure strain was maximum near the glass transition temperature (Tg) and significantly reduced above Tg. Also the CNT-modified epoxies showed improved toughness.