A nonvolatile memory device includes a device isolation pattern, a charge trap layer, and a plurality of word lines. The device isolation pattern defines an active region in a semiconductor substrate and extends in a first direction. The charge trap layer covers the active region and the device isolation pattern. The word lines on the charge trap layer cross the active region and extend in a second direction. The charge trap layer disposed in a first region where the word line and the active region cross each other has a different nitrogen content ratio from the charge trap layer disposed in a second region surrounding the first region.