To provide a thermoplastic elastomer composition having polarity which is excellent in surface wettability, high-frequency weldability, and oil resistance, and to provide a method for producing the same and a resin composition containing the thermoplastic elastomer.

The thermoplastic elastomer composition is obtained by dynamically crosslinking a mixed composition comprising (A) a vinyl polymer having 2 or more groups typified by a (meth)acryloyl group per one molecule, one or more of which being present at a terminal of the molecule, (B) a polyolefin resin, and (C) a plasticizer in the presence of (D) a radical initiator. There is also provide a method for producing the composition. There is also provided a resin composition comprising the composition and a polyolefin resin. The above target effect can be achieved by the above.