A refrigerator may prevent an internal door from being opened together by an inertial force when an external door is opened, and may also prevent the external door from being opened together by an inertial force when the internal door is opened. The refrigerator includes a main body, a storage chamber provided in the main body so that a front surface thereof is opened, an internal door rotatably provided at a front surface of the main body so as to open and close the storage chamber and having an opening part in which a plurality of door guards are provided, an external door rotatably provided at a front surface of the internal door so as to open and close the opening part, and an internal door opening prevention device allowing or preventing opening of the internal door according to whether the external door is opened or closed.