A memory device includes first and second bank groups, an internal command generator, and an address input/output circuit. Each of the bank groups includes a plurality of banks. The internal command generator generates and outputs internal commands to a first target bank. The internal commands are generated based on a command from a memory controller for controlling a memory operation of the first target bank. The address input/output (I/O) circuit receive a first address corresponding to the command, selects a storage path of the first address based on whether there is a bubble interval in a data burst operation interval corresponding to the first command, controls output of the first address in accordance with a time point at which each of the internal commands is output. The first address is stored in the address I/O circuit.