Defective (dead) pixels are pixels on a liquid crystal display (LCD) that are not performing as expected. The ISO standard ISO 13406-2 distinguishes between three different types of defective pixels, while hardware companies tend to have further distinguishing types.

Similar defects can also occur in a charge-coupled device (CCD) or CMOS image sensor in digital cameras. In these devices, defective pixels fail to sense light levels correctly, whereas defective pixels in LCDs fail to reproduce light levels correctly.