An olefin-acrylic ester copolymer-thermoplastic resin composition comprising one part by weight of an olefin-acrylic ester copolymer and 0.01 to 100 parts by weight of at least one thermoplastic resin having a modulus of elasticity of 10.sup.3 to 10.sup.5 kg/cm.sup.2 at room temperature and selected from the group consisting of crystalline thermoplastic resins and non-crystalline thermoplastic resins having a second-order transition point of 10.degree. C. or higher. The said composition is excellent in impact resistance, resistance to water, and alkali resistance and has improved surface characteristics as well as improved low temperature characteristics.