A thermoplastic resin composition, a method for manufacturing the same, and a molded body are provided. The composition includes a polyolefin resin PO, a polyimide resin PA, and a compatibilizer. The composition has a first phase composed of the PA and compatibilizer and/or a reaction product thereof and a second phase composed of the PO and interposed between the first phases. The first phase has a matrix phase composed of the PA and a dispersed phase dispersed in the matrix phase and composed of the compatibilizer and/or a reaction product thereof. The first phase includes a branched phase having branch portions. The method includes melt-kneading the PA and compatibilizer so that a mixing ratio of the compatibilizer is 11% by mass or more but 45% by mass or less per 100% by mass of a total of the PO, PA, and compatibilizer, and melt-kneading an obtained composition and the PO.