The present invention relates to an ice maker for a refrigerator. The present invention provides an ice maker for a refrigerator, which is provided at one side of the refrigerator to make ice. The ice maker comprises an ice maker body provided with an ice-making tray for making ice; an ejector rotatably mounted at one side of the ice maker body so as to eject ice made in the ice-making tray to the outside; a water supply hopper provided at one side of the ice maker body and having at least an open portion so that the water supply hopper is supplied with water from a water supply source through a water supply tube and then transfers the water to the ice-making tray; and a hopper cover coupled to the water supply hopper so as to selectively open and close the open portion of the water supply hopper. According to the present invention, it is possible to avoid a phenomenon in which water supplied from an outer water supply source to the water supply hopper splashes to the outside.