A display device includes a pixel connected to a data line, a data pad connected to the data line, and a first test area. The first test area includes a test control line transmitting a test control signal, a test signal line transmitting a test signal, and a first switch connected to the data pad. The first switch includes a gate electrode connected to the test control line, first and second semiconductor layers overlapping the gate electrode, a source electrode connected to the first and second semiconductor layers, and a drain electrode spaced from the source electrode and connected to the first and second semiconductor layers. The source electrode and the drain electrode are connected to the test signal line and data pad, respectively. One of the first or second semiconductor layers includes an oxide semiconductor and the other of the first or second semiconductor layer includes a silicon-based semiconductor.