An organic light emitting display device includes a substrate, a light emitting structure, a first conductive pattern, and a functional module. The substrate has an opening region, a peripheral region surrounding the opening region, and a display region surrounding the peripheral region, and includes a first groove, which has an enlarged lower portion, formed in the peripheral region and an opening formed in the opening region. The light emitting structure is in the display region on the substrate. The first conductive pattern overlaps the first groove in the peripheral region on the substrate. The functional module is in the opening of the substrate.