An optical touch display device includes a display unit and at least one light sensing module. The display unit includes a first substrate and a display layer. The first substrate has a display area and a non-display area surrounding the display area. The display layer is disposed on the display area of the first substrate. The light sensing module is disposed on an upper surface of the non-display area of the first substrate. A side surface of the light sensing module has a light sensing window, and at least a portion of the light sensing window is adapted to receive light above the display unit. The optical touch display device has a thin thickness.