The disclosure relates to a wall mounted washing machine and a rear panel thereof. The wall mounted washing machine includes a rear panel operable to be mounted on a wall and including a plurality of rear surface ribs on a rear surface thereof; a tub supported on the rear panel, the tub for containing wash water; a front panel having an opening formed therein and installed in the tub; a detergent container in one side of the front panel and containing a detergent and a softener; a drum rotatably installed in the tub; a cover installed on the front panel and covering the front panel; a door rotatably coupled to the cover for opening or closing the laundry inlet of the cover; a cabinet coupled to the rear panel and surrounding the tub; an exhaust line provided on a rear surface of the rear panel and exhausting air inside the tub; and a drain unit discharging wash water filled in the tub and connected to the exhaust line. The rear surface ribs includes a plurality of first rear surface ribs provided on an outer
