An operating method of a memory controller controlling a nonvolatile memory device including a plurality of pages includes receiving a read request and a logical address from an additional device; determining a program state of an upper unselected word line of a selected word line corresponding to the received logical address; and transmitting a physical address corresponding to the logical address, state information, and a read command to the nonvolatile memory device according to a result of the determination in response to the read request, wherein the state information indicates a level of a first unselect read voltage the nonvolatile memory device is to apply to the upper unselected word line.