Thermoplastic resin composition

The present invention provides a thermoplastic resin composition which comprises: a first polymer formed by graft polymerization of a diene-based rubber polymer with an aromatic vinyl-based monomer and a vinyl cyanide-based monomer; a second polymer comprising an aromatic vinyl-based monomer unit and a vinyl cyanide-based monomer unit; a third polymer formed by graft polymerization of an olefin-based polymer with an aromatic vinyl-based monomer and a vinyl cyanide-based monomer; and a fourth polymer comprising an olefin-based monomer unit and having a density of 0.92 to 0.94 g/cm3 as measured in accordance with ASTM D1505, a softening point of 100 to 120° C. as measured in accordance with ASTM D1525, and a melt flow index of 5 to 7 g/10 min as measured in accordance with ASTM D1238 at 190° C. and 2.16 kg, wherein the thermoplastic resin composition comprises the fourth polymer at 1 to 10 wt %.