Disclosed is a memory module which includes a memory chip; an external input/output terminal having an electrical signal input/output terminal and an optical signal input/output terminal; an optical signal processor configured to convert a first optical signal input through the optical signal input/output terminal into a first internal electrical signal and to convert a second internal electrical signal into a second optical signal; and a controller configured to provide a first data signal to the memory chip in response to a first external electrical signal input through the electrical signal input/output terminal or the first internal electrical signal and to transfer the second internal electrical signal to the optical signal processor or to output a second external electrical signal to the electrical signal input/output terminal in response to a second data signal output from the memory chip.