A refrigerator includes a cabinet that defines a first storage compartment configured to store food, a main door rotatably mounted on the cabinet and configured to open or close at least a portion of the first storage compartment, an accommodation device accessible through an opening in the main door, a sub door mounted on the main door and configured to open or close the opening, and a door opening assembly that is configured to selectively restrict one side of a back surface of the sub door to a corresponding side of a front surface of the main door to thereby selectively restrict movement of the sub door relative to the main door. The accommodation device defines a second storage compartment within the main door that is separated from the first storage compartment, and the door opening assembly is configured to be manipulated from a side surface of the sub door.