The present disclosure provides a thin film transistor, a method for fabricating the same, a display substrate, and a display apparatus, and belongs to the field of display technology. The method includes: forming a metal oxide semiconductor pattern comprising first and second metal oxide semiconductor layers, the second metal oxide semiconductor layer being above the first metal oxide semiconductor layer; depositing a source-drain metal layer on the metal oxide semiconductor pattern; etching the source-drain metal layer and the second metal oxide semiconductor layer to form source and drain electrodes and an active layer of the thin film transistor. The active layer is obtained after removing the second metal oxide semiconductor layer between the source and drain electrodes using a first etchant, and the first etchant has a higher etching rate on the second metal oxide semiconductor layer than on the first metal oxide semiconductor layer.