A thin film transistor includes an oxide semiconductor layer having a polycrystalline structure, a metal oxide layer in contact with the oxide semiconductor layer, a gate electrode provided so as to overlap the oxide semiconductor layer, a gate insulating layer provided between the oxide semiconductor layer and the gate electrode. The oxide semiconductor layer includes a plurality of crystal grains, each of which has at least one of a crystal orientation <101>, a crystal orientation <111>, and a crystal orientation <001> that are measured by an electron backscatter diffraction method. The oxide semiconductor layer includes a first region in which the crystal orientation <101> is oriented within 15 degrees with respect to a normal direction of a surface of the semiconductor layer. An occupancy ratio of the first region is greater than or equal to 20%.