Refrigerator comprising an ice maker assembly disposed in a storage space of the refrigerator, the ice maker assembly comprising: an ice maker unit configured to form ice; and a basket unit configured to store the ice formed in the ice maker unit, wherein the ice maker unit includes: a first and a second frames mounted at the refrigerator; a tray mounted at the first frame and comprising a space in which the ice is formed; and a water tank tiltably mounted at the second frame and configured to supply water to the tray, wherein the water tank comprises a rotating protrusion disposed at a side surface thereof, the water tank comprises a guide protrusion disposed at the side surface thereof and configured to guide a tilting motion of the water tank, and a mounting guide configured to guide the movement of the guide protrusion is disposed at the second frame, and wherein, when the water tank is tilted in a first direction, water stored in the water tank is supplied to the tray and the water tank is closed, and characterized in that the mounting guide includes a first accommodator configured such that the guide protrusion is movably inserted therein and a second accommodator configured such that the rotating protrusion is inserted therein, and the guide protrusion moves along the first accommodator when the rotating protrusion rotates in the second accommodator, the first accommodator and the second accommodator being formed by a single bent rib, and when the water tank is tilted in a second direction opposite to the first direction, the water tank is opened, so that water may be supplied to the water tank while the water tank is mounted on the frame. an ice maker unit configured to form ice; and a basket unit configured to store the ice formed in the ice maker unit, wherein the ice maker unit includes: a first and a second frames mounted at the refrigerator; a tray mounted at the first frame and comprising a space in which the ice is formed; and a water tank tiltably mounted at the second frame and configured to supply water to the tray, wherein the water tank comprises a rotating protrusion disposed at a side surface thereof, the water tank comprises a guide protrusion disposed at the side surface thereof and configured to guide a tilting motion of the water tank, and a mounting guide configured to guide the movement of the guide protrusion is disposed at the second frame, and wherein, when the water tank is tilted in a first direction, water stored in the water tank is supplied to the tray and the water tank is closed, and characterized in that the mounting guide includes a first accommodator configured such that the guide protrusion is movably inserted therein and a second accommodator configured such that the rotating protrusion is inserted therein, and the guide protrusion moves along the first accommodator when the rotating protrusion rotates in the second accommodator, the first accommodator and the second accommodator being formed by a single bent rib, and when the water tank is tilted in a second direction opposite to the first direction, the water tank is opened, so that water may be supplied to the water tank while the water tank is mounted on the frame. a first and a second frames mounted at the refrigerator; a tray mounted at the first frame and comprising a space in which the ice is formed; and a water tank tiltably mounted at the second frame and configured to supply water to the tray, wherein the water tank comprises a rotating protrusion disposed at a side surface thereof, the water tank comprises a guide protrusion disposed at the side surface thereof and configured to guide a tilting motion of the water tank, and a mounting guide configured to guide the movement of the guide protrusion is disposed at the second frame, and wherein, when the water tank is tilted in a first direction, water stored in the water tank is supplied to the tray and the water tank is closed, and characterized in that the mounting guide includes a first accommodator configured such that the guide protrusion is movably inserted therein and a second accommodator configured such that the rotating protrusion is inserted therein, and the guide protrusion moves along the first accommodator when the rotating protrusion rotates in the second accommodator, the first accommodator and the second accommodator being formed by a single bent rib, and when the water tank is tilted in a second direction opposite to the first direction, the water tank is opened, so that water may be supplied to the water tank while the water tank is mounted on the frame.