A mask assembly may include a frame, first sticks, and masks. The first sticks may extend in a first direction and may be arranged in a second direction. The plurality of masks may be disposed on the frame and the first sticks. The plurality of masks may extend in the second direction and may be arranged in the first direction. Each of the first sticks may have a first edge and a second edge, which are opposite to each other in the second direction. When viewed in a plan view defined by the first and second directions, the first and second edges of an outermost stick of the first sticks may have different shapes, and linear lengths of the first and second edges of the outermost stick may be substantially equal to each other, where the linear lengths are lengths of the first and second edges in a straight state.