Researchers have investigated the effects of different nanoenhancers on the physical properties of polymer-based nanocomposites. However, the effect of resin type on the properties of nanocomposites reinforced by multiwalled carbon nanotube (MWCNT) has not been studied very well. This study aims to understand the link between the nature of polymer as the base material for nanocomposite and the reinforcement role of MWCNT. Three common polymers, with high industrial applications, namely vinyl ester, polyester and epoxy were chosen. The standard tensile specimens were prepared for both neat and reinforced resins using 0.5 wt % of MWCNTs. The results indicated that while for the vinyl ester and polyester resins there was no improvement in the elastic modulus, for the epoxy resin the elastic modulus increases by 5.6% with addition of MWCNT. On the other hand, the electrical test results showed that electrical conductivity was greatly increased in the presence of MWCNT, for both vinyl ester and epoxy resins. But for the polyester resin, little improvement was observed with the addition of MWCNT. The mechanisms causing this trend were investigated. Moreover, several optical microscopy and scanning electron microscopy images were taken from the fracture surfaces to evaluate the surface features and fracture mechanisms.