A thermoplastic resin composition comprising: polypropylene; and a polyolefin-polystyrene-based multi-block copolymer satisfying the following conditions (a) to (c) measured from Gel Permeation Chromatography (GPC) and the following condition (d) in 13 C NMR (500 MHz, tetrachloroethane-d2, standard material TMS) spectrum: (a) a weight average molecular weight is 50,000 to 300,000 g/mol, (b) a molecular weight distribution is 1.5 to 3.0, (c) for gel permeation chromatography measurement results, a Gaussian function modeled from a graph having logMw as an x-axis and dw/dlogMw as a y-axis is represented by Equation 1 below, wherein in Equation 1 below, each constant value satisfies -0.05 < A < 0.06, 4.6 < B < 5.5, 0.9 < C < 1.1, and 0.5 < D < 0.9, and (d) a polyolefin block included in the polyolefin-polystyrene-based multi-block copolymer includes one or more branching points, wherein a carbon atom of the branching points exhibits a peak of 36 to 40 ppm, and a terminal carbon atom of a branched chain branched from the branching point exhibits a peak of 13 to 15 ppm, dw dlogMw = A + Cexp − 4 ln 2 logMw − B 2 D 2 D π 4 ln 2 wherein in Equation 1 above, Mw represents the weight average molecular weight of a polyolefin-polystyrene-based multi-block copolymer. polypropylene; and a polyolefin-polystyrene-based multi-block copolymer satisfying the following conditions (a) to (c) measured from Gel Permeation Chromatography (GPC) and the following condition (d) in 13 C NMR (500 MHz, tetrachloroethane-d2, standard material TMS) spectrum: (a) a weight average molecular weight is 50,000 to 300,000 g/mol, (b) a molecular weight distribution is 1.5 to 3.0, (c) for gel permeation chromatography measurement results, a Gaussian function modeled from a graph having logMw as an x-axis and dw/dlogMw as a y-axis is represented by Equation 1 below, wherein in Equation 1 below, each constant value satisfies -0.05 < A < 0.06, 4.6 < B < 5.5, 0.9 < C < 1.1, and 0.5 < D < 0.9, and (d) a polyolefin block included in the polyolefin-polystyrene-based multi-block copolymer includes one or more branching points, wherein a carbon atom of the branching points exhibits a peak of 36 to 40 ppm, and a terminal carbon atom of a branched chain branched from the branching point exhibits a peak of 13 to 15 ppm, dw dlogMw = A + Cexp − 4 ln 2 logMw − B 2 D 2 D π 4 ln 2 wherein in Equation 1 above, Mw represents the weight average molecular weight of a polyolefin-polystyrene-based multi-block copolymer. (a) a weight average molecular weight is 50,000 to 300,000 g/mol, (b) a molecular weight distribution is 1.5 to 3.0, (c) for gel permeation chromatography measurement results, a Gaussian function modeled from a graph having logMw as an x-axis and dw/dlogMw as a y-axis is represented by Equation 1 below, wherein in Equation 1 below, each constant value satisfies -0.05 < A < 0.06, 4.6 < B < 5.5, 0.9 < C < 1.1, and 0.5 < D < 0.9, and (d) a polyolefin block included in the polyolefin-polystyrene-based multi-block copolymer includes one or more branching points, wherein a carbon atom of the branching points exhibits a peak of 36 to 40 ppm, and a terminal carbon atom of a branched chain branched from the branching point exhibits a peak of 13 to 15 ppm, dw dlogMw = A + Cexp − 4 ln 2 logMw − B 2 D 2 D π 4 ln 2 wherein in Equation 1 above, Mw represents the weight average molecular weight of a polyolefin-polystyrene-based multi-block copolymer. <EOS>