A mask frame assembly for thin film deposition is disclosed. In one embodiment, the assembly includes: a frame, and a plurality of unit mask strips attached to the frame, wherein each of the unit mask strips includes a plurality of unit masking patterns which are spaced apart from each other. In one embodiment, each of the unit masking patterns includes: i) a plurality of stripe pattern slits and ii) a plurality of sets of dot pattern slits each set formed to be substantially parallel with the stripe pattern slits. Further, the stripe pattern slits and the sets of dot pattern slits are alternately formed with respect to each other, wherein each set of the dot pattern slits includes a plurality of dot pattern slits, and wherein the length of each stripe pattern slit is substantially the same as the length of each set of the dot pattern slits.