Rational distribution and orientation of boron nitridenanosheets (BNNSs) are very significant for a polymer/BNNScomposite to obtain a high thermal conductivity at low filler content.In this paper, a high-performance thermal interface material based onexfoliated BNNSs and polystyrene (PS) microspheres was fabricatedby latex blending and subsequent compression molding. In this case,BNNSs and PS microspheres first self-assembled to form the complexmicrospheres via strong electrostatic interactions between them. Theas-prepared complex microspheres were further hot-pressed aroundthe glass transition temperature, which brought the selectivedistribution of BNNSs at the interface of the deformed PSmicrospheres. As a consequence, a polymer composite withhomogeneous dispersion and high in-plane orientation of BNNSs inPS matrix was obtained. Benefitted from this unique structure, the resultant composite exhibits a significant thermal conductivityenhancement of 8.0 W m−1 K−1 at a low filler content of 13.4 vol %. This facile method provides a new strategy to design andfabricate highly thermally conductive composites.KEYWORDS: boron nitride, polystyrene microspheres, electrostatic interaction, orientation, thermal conductivity, polymer composite