There is provided a thermoplastic elastomer composition including an ethylene/α-olefin copolymeric rubber (A1) or an extended rubber (X) comprising an ethylene/α-olefin copolymeric rubber (A2) and a mineral oil softener (E2), and a thermoplastic α-olefin resin (B) comprising a α-olefinic crystalline thermoplastic resin (B1) and/or a α-olefinic amorphous thermoplastic resin (B2), an unmodified organopolysiloxane (C), a viny-terminated organopolysiloxane (D), and a mineral oil softener (E1); and molded article produced by forming the thermoplastic elastomer composition. There is provided a thermoplastic elastomer composition and a molded article thereof having excellent molding appearance by imparting an initial sliding ability with an organopolysiloxane having low viscosity and by adding a crosslinked vinylated organopolysiloxane to a thermoplastic elastomer composition to exhibit durable abrasion resistance (long term sliding ability).