A display apparatus, a multi display system including the same, and a control method thereof are provided. The display apparatus includes a display configured to display a first image corresponding to a first image signal on a main screen, and a second image corresponding to a second image signal on a picture in picture (PIP) screen overlapping an area of the main screen. The display apparatus further includes a communication interface configured to transmit and receive information of a movement of the PIP screen to and from another display apparatus, and a controller configured to control the display to move the PIP screen based on the information.