Provided is a thermoplastic resin composition which comprises: a first copolymer comprising an alkyl acrylate-based rubber polymer, aromatic vinyl-based units, and vinyl cyan-based units; a second copolymer comprising an alkyl acrylate-based rubber polymer, aromatic vinyl-based units, and vinyl cyan-based units; a third copolymer comprising aromatic vinyl-based units and vinyl cyan-based units; a fourth copolymer comprising aromatic vinyl-based units and vinyl cyan-based units; and a fifth copolymer comprising maleimide-based units, aromatic vinyl-based units, and vinyl cyan-based units, wherein the first and second copolymers comprise alkyl acrylate-based rubber polymers with mutually different average particle sizes, and the third and fourth copolymers have mutually different weight average molecular weights.