A programming method of a nonvolatile memory device includes inputting even data and odd data to be programmed into even memory cells coupled to even bit lines and odd memory cells coupled to odd bit lines, respectively, setting a sense signal as a first sense signal or a second sense signal having a lower voltage level than the first sense signal, based on odd data of odd memory cells adjacent to each of the even memory cells to be programmed, programming the even data into the even memory cells by supplying a program voltage, performing a program verify operation on each of the even memory cells in response to the set sense signal, and programming the odd data into the odd memory cells by supplying a program voltage.