The disclosure discloses a thin film transistor and a display panel. The thin film transistor includes a gate, a source, a drain, an active layer, and a heat transmitting layer; wherein the heat transmitting layer is arranged on a side of the active layer. In the disclosure, the heat of the active layer may be promptly conducted to the surrounding environment, so as to prevent the self-heating effect of the thin film transistor from affecting the normal working state.