Disclosed is a washing machine enabling to prevent foam from leaking. The present invention includes a housing, a tub installed in the housing to store water, the tub having at least one opening and at least one pipe connected to the at least one opening, a drum rotatably installed in the tub to hold a laundry therein for washing, and a valve assembly installed at the opening to selectively cut off the at least one pipe to prevent foam produced in the drum and the tub from leaking outside via the opening.