A transparent thermoplastic resin composition includes (A) a rubber-modified graft copolymer which is prepared by copolymerizing (a2) a (meth)acrylic acid alkyl ester monomer, (a3) a styrene-based monomer and (a4) an acrylonitrile-based monomer onto (a1) a butadiene-based rubber polymer; (B) a styrene-based copolymer having a glass transition temperature of about 90 to about 100° C. which is prepared by copolymerizing (b1) a methacrylic acid alkyl ester monomer, (b2) an acrylic acid alkyl ester monomer, (b3) a styrene-based monomer and (b4) an acrylonitrile-based monomer; and (C) a silicone oil. The composition can have improved whitening resistance at low temperatures and/or excellent impact strength.