A thermoplastic resin composition, comprising: 100 parts by weight of a base resin comprising 5 to 40 % by weight of a vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (a) containing conjugated diene rubber having a particle diameter of 0.05 μm to 0.2 μm, 5 to 40 % by weight of a vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (b) containing conjugated diene rubber having a particle diameter of greater than 0.2 μm and less than or equal to 0.5 μm, and 50 to 80 % by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (c); and more than 0.01 parts by weight and less than 2 parts by weight of a compound represented by Formula 1 below: wherein X is hydrogen or a hydroxyl group, Y is hydrogen or R 1 and R 2 are each independently an alkyl group having 1 to 10 carbon atoms, R 3 and R 4 are each independently an aryl group having 6 to 12 carbon atoms or an alkyl group having 1 to 10 carbon atoms, R 5 and R 6 are each independently an alkyl group having 1 to 10 carbon atoms, Z is hydrogen or a hydroxyl group, n is an integer of 1 to 100, and m is an integer of 0 to 100, wherein the content of the vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (a) is less than the content of the vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (b), and the kinematic viscosity (25 °C) of the compound represented by Formula 1 is greater than 5 cSt and less than 200 cSt, wherein the weight ratio of the vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (a) to the vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (b) is 1:1.5 to 4, wherein the particle diameter of the conjugated diene rubber means the average particle diameter of conjugated diene rubber particles measured using dynamic laser light scattering and intensity Gaussian distribution (Nicomp 380), and wherein the kinematic viscosity is obtained by dividing absolute viscosity by density, and absolute viscosity is measured at 25 °C according to ASTM D445-46T. 100 parts by weight of a base resin comprising 5 to 40 % by weight of a vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (a) containing conjugated diene rubber having a particle diameter of 0.05 μm to 0.2 μm, 5 to 40 % by weight of a vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (b) containing conjugated diene rubber having a particle diameter of greater than 0.2 μm and less than or equal to 0.5 μm, and 50 to 80 % by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (c); and more than 0.01 parts by weight and less than 2 parts by weight of a compound represented by Formula 1 below: wherein X is hydrogen or a hydroxyl group, Y is hydrogen or R 1 and R 2 are each independently an alkyl group having 1 to 10 carbon atoms, R 3 and R 4 are each independently an aryl group having 6 to 12 carbon atoms or an alkyl group having 1 to 10 carbon atoms, R 5 and R 6 are each independently an alkyl group having 1 to 10 carbon atoms, Z is hydrogen or a hydroxyl group, n is an integer of 1 to 100, and m is an integer of 0 to 100, wherein the content of the vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (a) is less than the content of the vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (b), and the kinematic viscosity (25 °C) of the compound represented by Formula 1 is greater than 5 cSt and less than 200 cSt, wherein the weight ratio of the vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (a) to the vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer (b) is 1:1.5 to 4, wherein the particle diameter of the conjugated diene rubber means the average particle diameter of conjugated diene rubber particles measured using dynamic laser light scattering and intensity Gaussian distribution (Nicomp 380), and wherein the kinematic viscosity is obtained by dividing absolute viscosity by density, and absolute viscosity is measured at 25 °C according to ASTM D445-46T.