The present invention relates to a thermoplastic resin composition. More particularly, the present invention relates a thermoplastic resin composition including 100 parts by weight of a base resin including (a) an aromatic vinyl compound-conjugated diene-based compound-vinyl cyan compound copolymer and (b) an aromatic vinyl compound-vinyl cyan compound copolymer; and (c) greater than 0.05 parts by weight and less than 11 parts by weight of a polyolefin oxide-based triblock copolymer, and a molded article including the same. In accordance with the present invention, the thermoplastic resin composition having superior chemical resistance and paintability with identical or superior impact strength, fluidity, and heat resistance, to conventional thermoplastic resin compositions, and a molded article including the same are provided.