A mask assembly includes a mask frame in which a first opening is defined, the mask frame including a front surface through which the first opening extends, and a deposition mask which is attached to the front surface of the mask frame and through which a plurality of second openings is defined. The mask frame includes an in which the front surface extends along a direction of gravity, the deposition mask includes an initial mask which is attached to the front surface of the mask frame in the thereof and through which the plurality of second openings is defined, and the of the mask frame having the front surface which extends along the direction of gravity disposes the first opening of the mask frame corresponding to all of the plurality of second openings of the initial mask along the direction of gravity.