An ice tray assembly for a refrigerator is provided, which includes a case; at least one ice tray disposed in the case; a water box provided at a lateral surface of the ice trays to supply water to the ice trays; and at least one discharge hole provided at the water box corresponding to the number of the ice trays. According to the present invention, the ice tray assembly for the refrigerator is capable of supplying water to the plurality of ice trays at once, of easily supplying water to the ice trays disposed at an upper layer portion in general, as the water box is disposed at the lateral surface of the ice trays, and of uniformly supplying water to each of the plurality of the ice trays.