The application provides a thin film transistor, a method for manufacturing the thin film transistor, and a display panel, the thin film transistor includes a metal electrode, and a step of forming the metal electrode includes: forming a first material layer on a substrate; performing a pattering process on the first material layer to form a groove pattern in the first material layer such that the groove pattern matches with a pattern of the metal electrode to be formed; forming the metal electrode in the groove pattern such that a gap is formed between an edge of the metal electrode and an edge of the groove pattern; forming a protection pattern on the substrate formed with the metal electrode such that the protection pattern covers the metal electrode and its edge. In the application, the protection pattern is formed on the resultant metal electrode and can effectively protect conductive metal.