A polyolefin resin composition is disclosed which comprises (a) a crystalline propylene polymer in an amount of 40% or more to less than 95% by weight, (b) an ethylene/.alpha.-olefin rubber in an amount of from 5 to 40% by weight, and (c) a linear or branched specified block copolymer in an amount of from 0.1 to 20% by weight containing a polyethylene block segment A having a melting temperature as measured with a differential scanning calorimeter of from 80.degree. to 120.degree. C. and an ethylene/.alpha.-olefin copolymer block segment B, the total content of components (a), (b), and (c) being 100% by weight, which composition has excellent dispersibility of the rubber used, so that moldings having an excellent balance between rigidity and impact resistance are obtained therefrom, and is hence suitable for use in the field of moldings required to have rigidity and impact resistance.