A wall mounted washing machine and a water supply valve assembly thereof are provided to reduce cost in the assembly process. The wall mounted washing machine includes a rear panel mounted on a wall; a tub supported on the rear panel, the tub being filled with wash water; a front panel having an opening formed therein and installed in the tub; a drum rotatably installed in the tub; a cover installed on the front panel to cover the front panel; a door rotatably coupled to the cover to open or close a laundry inlet of the cover; a cabinet coupled between the rear panel and the cover; and a water supply valve assembly installed on the front panel with respect to an inner lower space of the cabinet.