A method of operating a nonvolatile memory device may include applying a first voltage greater than a ground voltage to a selected word line during a first time period; applying a second voltage to an unselected word line during a second time period that is later than the first time period; and applying a third voltage greater than the first voltage and the second voltage to the selected word line during the second time period. The second time period includes a third time period during which a voltage level of the unselected word line increases to the second voltage from a fourth voltage that is less than the second voltage, and during which a voltage level of the selected word line increases to the third voltage from the first voltage.