A graft copolymer has good moldability and good continuous moldability, and a thermoplastic resin molded article having excellent impact resistance can be produced. A method can produce the graft copolymer. A graft copolymer (B-I) produced by grafting at least one vinyl monomer (b-I) selected from the group consisting of an aromatic vinyl, an alkyl (meth)acrylate, and a vinyl cyanide to a rubbery polymer mixture including a rubbery polymer (A-I) and a hydrophobic substance, the rubbery polymer (A-I) including an alkyl (meth)acrylate unit and a multifunctional monomer unit copolymerizable with the alkyl (meth)acrylate, the hydrophobic substance having a kinematic viscosity of 5 mm2/s or more at 40° C. or a kinematic viscosity of 2 to 4 mm2/s at 100° C., a principal constituent of the hydrophobic substance being a hydrocarbon. A thermoplastic resin composition includes the graft copolymer (B-I). A molded article produced uses the thermoplastic resin composition.