A mask assembly, an apparatus for manufacturing a display device, and a method of manufacturing a display device are provided. A mask assembly includes: a mask frame including a frame body portion and dividers, the frame body portion being arranged at an outside of the mask frame, and the dividers dividing an inside of the frame body portion into a plurality of openings, each of the dividers being connected in a first direction and a second direction; and a plurality of mask sheets arranged on a top surface of the mask frame, coupled to the mask frame, and including at least one pattern opening, mask sheets of the plurality of mask sheets being apart from each other in the first direction.