Provided are a memory device and a memory system including the same. The memory device may include a data bus inversion (DBI) mode selector configured to select a first multi-bit DBI signal from among a plurality of multi-bit DBI signals respectively corresponding to a plurality of DBI modes according to multi-bit data; a multi-mode DBI encoder configured to generate encoded multi-bit data by DBI encoding the multi-bit data according to the first multi-bit DBI signal; and a transceiver configured to transmit a data symbol corresponding to the encoded multi-bit data through a data channel and transmit a DBI symbol corresponding to the first multi-bit DBI signal through a DBI channel.