Ambipolar hybrid transistors were fabricated by using inorganic zinc oxide (ZnO) nanoparticles and an organic polymer, poly(3-hexylthiophene) (P3HT), as n - and p -type semiconductors, respectively. With well-adjusted ratio between n - and p -type, an ambipolar transport was observed in thin films based on either bilayer ZnO/P3HT or blend ZnO:P3HT architectures. Morphology of solution-processed thin films was studied by scanning electron microscopy (SEM). A hybrid interface was formed by the direct contact between ZnO and P3HT leading to carrier redistribution. Such solution-processed hybrid thin-film transistors delivered in air well balanced electron and hole mobilities for both bilayer and blend architectures.