Provided is a display apparatus and a method of operating the same. The display apparatus includes: a power supply configured to generate power to be supplied to the display apparatus from an external power source, an input interface configured to receive a turn-on command or a turn-off command for the display apparatus, a main module configured to operate at an operation voltage and control the input interface to receive the turn-off command, and a controller configured to operate at a standby voltage, wherein the controller is configured to: a first switch control signal to open a first switch to deliver the operation voltage to the main module based on the turn-off command, and output a second switch control signal to open a second switch connected between the external power source and the power supply based on the outputting of the first switch control signal.