A flame-retardant thermoplastic resin composition that can have excellent color tone according to the present invention comprises a base resin comprising (A) about 50 to about 99% by weight of a rubber modified aromatic vinyl resin; and (B) about 1 to about 50% by weight of an acryl resin; and further comprising (C) about 1 to about 30 parts by weight of a bromodiphenyl ethane mixture, based on about 100 parts by weight of the base resin comprising (A) and (B); and (D) about 1 to about 10 parts by weight of an antimony oxide, based on about 100 parts by weight of the base resin comprising (A) and (B). The resin composition of the present invention can have improved physical properties and color properties as well as flame resistance.