Elastomer-rich thermoplastic polyolefin (ETPO) resin containing 70 wt% maleated styrene-ethylene-butadiene-styrene (SEBS-g-MA) and 30 wt% polypropylene and its nanocomposites filled with 1–5 wt% SiC nanoparticles ( S i C p ) were fabricated using extrusion and injection molding techniques. The mechanical and thermal behaviors of ETPO and its nanocomposites were investigated. Tensile measurements showed that the S i C p additions lead to reductions in both tensile stiffness and strength of ETPO. However, Izod impact and EWF measurements indicated that the impact strength and fracture toughness of ETPO improve substantially with increasing S i C p content. This demonstrated that SiC nanoparticles toughen the ETPO blend effectively. Furthermore, S i C p additions were found to improve the thermal resistance of ETPO blend considerably.