The present invention provides a thermoplastic resin composition which includes: a first copolymer including a core including a conjugated diene-based polymer and a shell including an aromatic vinyl-based monomer unit and a vinyl cyan-based monomer unit; and a second copolymer including an aromatic vinyl-based monomer unit and a vinyl cyan-based monomer unit, wherein the first copolymer has a degree of grafting of 32 to 50%, the second copolymer has a weight-average molecular weight of 85,000 to 115,000 g/mol, and the thermoplastic resin composition includes the first copolymer at 30 wt % or less and an oligomer residue at 1.1 wt % or less. Specifically, the thermoplastic resin composition can shorten an injection molding time.