An organic light emitting device includes a first emitting part on an anode, the first emitting part including a first emission layer and a first hole transport layer a second emitting part on the first emitting part, the second emitting part including a second emission layer and a second hole transport layer; a third emitting part on the second emitting part including a third emission layer and a third hole transport layer; and a cathode on the third emitting part. The third emitting part further includes a fourth emission layer to emit light having a same color as the third emission layer and includes a dopant and a mixed host of at least two hosts, and a fourth hole transport layer provided on the third hole transport layer while in contact with the third emission layer, and has a hole mobility lower than that of the third hole transport layer.