A multi-display device includes a plurality of display modules and a host controller. Each of the display modules includes a display panel and a display driving integrated circuit and performs a display panel self-refresh operation. The host controller controls the display modules and provides image data for displaying an image to the display modules. The display modules are classified into a master display module and slave display modules that adjust a vertical blank period based on a reference tearing effect control signal output from the master display module. Thus, the multi-display device can mitigate or prevent a tearing effect from occurring between the display modules without changing an interface between the host controller and the display modules.