A mask assembly and an organic light emitting display device manufactured using the mask assembly are capable of realizing an organic light emitting display device having a hole in a display area, the mask assembly including a frame defining a first opening area, a first mask on the frame and defining a plurality of second opening areas that overlap the first opening area, and a second mask fixed to the frame across the plurality of second opening areas, and including a body portion overlapping the first mask, a blocking portion at each respective one of the second opening areas, and a pattern portion between the body portion and the blocking portion, and defining a plurality of holes.