1. A display device comprising:a panel having a plurality of gate lines and a plurality of data lines;
a data driver supplying data voltages to the plurality of data lines arranged in the panel;
a gate driver including a plurality of stage groups that are driven by independent external start signals to output scan signals to the plurality of gate lines, and
a timing controller configured to control the data driver not to output the data voltages to the plurality of data lines until (i) a start signal is supplied to one stage group of the plurality of stage groups, (ii) scan signals are output from the one stage group, and (iii) another start signal is supplied to another stage group,
wherein each of the plurality of stage groups comprises a stage disallowing a clock to be output as a scan signal responsive to receiving a stop signal.