Disclosed are a flame retardant thermoplastic resin composition suitable for preparing an electric wire, etc. by enhancing extrudability of a resin composition without hindering flame retardancy of the resin composition, and an electric wire comprising the same. The flame retardant thermoplastic resin composition comprises a matrix resin that comprises 20% to 40% by weight of a poly arylene ether resin, 20% to 40% by weight of a vinyl aromatic resin and 5% to 17% by weight of a polypropylene resin comprising a rubber ingredient, and 10% to 30% by weight of a flame retardant, based on a total weight of the resin composition.