A thin film transistor array panel and a manufacturing method thereof according to an exemplary embodiment of the present invention form a contact hole in a second passivation layer formed of an organic insulator, protect a side of the contact hole by covering with a protection member formed of the same layer as the first field generating electrode and formed of a transparent conductive material, and etch the first passivation layer below the second passivation layer using the protection member as a mask. Therefore, it is possible to prevent the second passivation layer formed of an organic insulator from being overetched while etching the insulating layer below the second passivation layer so that the contact hole is prevented from being made excessively wide.