An organic light emitting device and a method of manufacturing the same are disclosed. The organic light emitting device includes a substrate, a gate electrode on the substrate, a first insulating film insulating the gate electrode, a semiconductor layer positioned opposite to the gate electrode, a second insulating film insulating the semiconductor layer, source and drain electrodes connected to the semiconductor layer, a first electrode connected to one of the source and drain electrodes, a third insulating film including an opening that exposes the first electrode, a second electrode positioned opposite to the first electrode, and a light emitting layer positioned between the first electrode and the second electrode. A taper angle of an edge area of the third insulating film contacting the first electrode lies substantially in a range between 10° and 50°.