Provided herein may be a memory device and a method of operating the same. The memory device may include a memory block including a plurality of pages, and peripheral circuits configured to sequentially program the pages. The memory device may include control logic configured to control the peripheral circuits such that a program voltage is applied to a word line coupled to a page selected from among the pages such that different pass voltages are applied to all or some word lines coupled to pages on which a program operation has been performed among unselected pages other than the selected page, and to word lines coupled to pages on which a program operation has not been performed among the unselected pages.