Discussed is an organic light emitting display device. The organic light emitting display device in one embodiment includes a plurality of pixels configured to each include an organic light emitting device which emits light with a data current, and a pixel circuit that includes a driving transistor which supplies the data current, which is based on a difference voltage between a data voltage and a reference voltage, to the organic light emitting device, a plurality of data lines configured to respectively supply a plurality of the data voltages to the plurality of pixels, a plurality of gate lines configured to supply a gate signal to the pixels, and a plurality of reference lines connected to at least one of the pixels, and configured to supply the reference voltage to the connected pixel. The reference voltage is varied according to data of a pixel connected to a corresponding reference line.