A non-volatile memory device includes a semiconductor layer including a cell region and a peripheral region, a cell region gate structure disposed in the cell region of the semiconductor layer, and wherein the cell region gate structure includes a tunneling insulating layer and a first blocking insulating layer, a second blocking insulating layer, and a third blocking insulating layer. The no-volatile memory device further includes a peripheral region gate structure formed in the peripheral region of the semiconductor layer. The peripheral region gate structure includes a first peripheral region insulating layer including a same material as a material included in the tunneling insulating layer and a second peripheral region insulating layer including a same material as a material included in the third blocking insulating layer.