An organic light emitting display device includes a scan driver for supplying a first scan signal to a first scan line during a first period and a second period, a second scan signal to a second scan line during the second period, and a light emitting control signal to a light emitting control line during a period at least spanning the first and second periods. A data driver sequentially supplies data signals to an output line during the first period. A demultiplexer is electrically coupled to the output line, receives the data signals and supplies the data signals to data lines which are connected to pixels. Each pixel receives one of the data signals during the first period, compensates a threshold voltage of a driving transistor during the second period, and generates light with a brightness corresponding to the one of the data signals after the second period.