A thermoplastic resin composition comprising:(A) from 10 to 50% by weight of a maleimide copolymer of from 30 to 70 mol % of an aromatic vinyl monomer, from 30 to 50 mol % of a maleimide monomer, from 3 to 20 mol % of an unsaturated dicarboxylic anhydride monomer and from 0 to 50 mol % of other copolymerizable monomer;(B) from 40 to 80% by weight of a polyamide; and(C) from 3 to 40% by weight of a polyolefin polymer modified by from 0.1 to 10% by weight of an unsaturated dicarboxylic anhydride monomer and/or an unsaturated carboxylic acid monomer,wherein said maleimide copolymer is in the form of dispersed particles of from 0.01 to 1.0 .mu.m.