A mask for thin film deposition includes a first mask which defines an opening, and a second mask on a surface of the first mask, and which defines a plurality of deposition holes and has a multilayer structure, in which the opening and the plurality of deposition holes communicate with each other and provide a passage for a deposition material, a size of each of the plurality of deposition holes is smaller than a size of the opening, and each of the plurality of deposition holes has a shape corresponding to a deposition pattern to be patterned on a substrate.