A thermoplastic resin composition contains (i) a polylactic acid, (ii) a polyolefin, and (iii) a compatibilizer (functional group-containing polymer that includes a functional group selected from functional groups X including a carboxyl group, an acid anhydride group, an epoxy group, a (meth)acryloyl group, an amino group, an alkoxysilyl group, a hydroxyl group, an isocyanate group, and an oxazoline group). The thermoplastic resin composition contains (iii-1) a functional group-containing hydrogenated diene polymer and (iii-2) a functional group-containing olefin polymer as the component (iii).