Provided are a thermoplastic resin composition having high environmental stress crack resistance (ESCR) as well as excellent impact resistance and transparency and a thermoplastic resin molded article prepared therefrom. The thermoplastic resin composition includes a graft copolymer (A), in which a (meth)acrylic acid ester, a vinyl cyan-based compound, and an aromatic vinyl compound are graft polymerized with a conjugated diene-based rubber latex; and a copolymer (B) of a (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound in a weight ratio of 35:65 to 70:30. A difference in refractive indices of the graft copolymer (A) and the copolymer (B) of the (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound is less than 0.003 when irradiated with light having a wavelength of 450 nm to 680 nm, and a melt index is 4.0 g/10 min or less when the melt index is measured in accordance with ASTM D1238.