An X-Y stage driver having a locking device and a data storage system having the X-Y stage driver. The X-Y stage driver includes an X-Y stage; a supporting unit that supports the X-Y stage and has elastic beams that support corners of the X-Y stage; a driving unit that drives the X-Y stage in a first direction and a second direction which is perpendicular to the first direction; a stiffener that prevents the X-Y stage from rotating; and a locking device that fixes the stiffener by an electrostatic force.