The present invention relates to a polypropylene-based resin composition which exhibits mechanical properties such as excellent strength, etc. and has an improved impact strength, and to a molded article including the same. The olefin-based copolymer includes: a polypropylene-based resin; and an olefin-based copolymer, wherein the olefin-based copolymer includes polymeric fractions defined by three different peaks at a given temperature when analyzed by cross-fractionation chromatography (CFC).