A display apparatus having a display to display a picture thereon comprises a pivot sensor comprising a weight body, a housing in which the weight body is accommodated and movable as the display is pivoted, and a contact sensor placed in the housing and generating a sensing signal according to a pivoted angle of the display when contacting the weight body. A pivot sensing controller applies a predetermined driving voltage to the pivot sensor, and determines the pivot angle of the display on the basis of the sensing signal generated corresponding to the applied driving voltage. The pivot sensing apparatus requires a reduced number of pivot sensors and peripheral circuits to sense a pivot angle of a display panel. A display apparatus and system comprising the pivot sensing apparatus, and a method for sensing a pivot angle, are also disclosed.