The disclosure discloses a thin film transistor, a method for fabricating the same, and a display device so as to avoid a source and a drain from being oxidized while the thin film transistor is being fabricated, to thereby improve the performance of the thin film transistor. The method for fabricating a thin film transistor includes: forming an active layer pattern on a base substrate, and a source-drain metal layer located above the active layer pattern and with a same pattern as the active layer pattern, using one patterning process; forming a first insulation layer above the source-drain metal layer; and patterning the source-drain metal layer and the first insulation layer using one patterning process so that portion of the active layer pattern corresponding to a channel area is exposed to form a source pattern and a drain pattern.