A refrigerator comprising: a cabinet having a storage compartment defined therein; a door for opening and closing the storage compartment; and a water tank for supplying water to a user, wherein the water tank comprises: a storage unit for storing water; a valve for supplying the water stored in the storage unit to the user; and a cover for opening and closing the storage unit, characterized in that the water tank is provided at an inside of the door and in that the cover comprises: a cover support part protruding to one side such that the cover support part is supported at an upper side of the storage unit; and the cover further comprises: a main cover; and an auxiliary cover fastened to a lower part of the main cover, a hollow part being defined therein and defined by the main cover and the auxiliary cover, a gasket comprising a protrusion protruding toward an inside wall of the storage unit, and a body provided in the hollow part, the body being connected to the protrusion. a cabinet having a storage compartment defined therein; a door for opening and closing the storage compartment; and a water tank for supplying water to a user, wherein the water tank comprises: a storage unit for storing water; a valve for supplying the water stored in the storage unit to the user; and a cover for opening and closing the storage unit, characterized in that the water tank is provided at an inside of the door and in that the cover comprises: a cover support part protruding to one side such that the cover support part is supported at an upper side of the storage unit; and the cover further comprises: a main cover; and an auxiliary cover fastened to a lower part of the main cover, a hollow part being defined therein and defined by the main cover and the auxiliary cover, a gasket comprising a protrusion protruding toward an inside wall of the storage unit, and a body provided in the hollow part, the body being connected to the protrusion. a storage unit for storing water; a valve for supplying the water stored in the storage unit to the user; and a cover for opening and closing the storage unit, characterized in that the water tank is provided at an inside of the door and in that the cover comprises: a cover support part protruding to one side such that the cover support part is supported at an upper side of the storage unit; and the cover further comprises: a main cover; and an auxiliary cover fastened to a lower part of the main cover, a hollow part being defined therein and defined by the main cover and the auxiliary cover, a gasket comprising a protrusion protruding toward an inside wall of the storage unit, and a body provided in the hollow part, the body being connected to the protrusion. a cover support part protruding to one side such that the cover support part is supported at an upper side of the storage unit; and the cover further comprises: a main cover; and an auxiliary cover fastened to a lower part of the main cover, a hollow part being defined therein and defined by the main cover and the auxiliary cover, a gasket comprising a protrusion protruding toward an inside wall of the storage unit, and a body provided in the hollow part, the body being connected to the protrusion. a main cover; and an auxiliary cover fastened to a lower part of the main cover, a hollow part being defined therein and defined by the main cover and the auxiliary cover, a gasket comprising a protrusion protruding toward an inside wall of the storage unit, and a body provided in the hollow part, the body being connected to the protrusion.