A display may have an array of pixels. Each pixel may have a light-emitting diode such as an organic light-emitting diode. The organic light-emitting diodes may each have an anode that is coupled to a thin-film transistor pixel circuit for controlling the anode. Transparent windows may be formed in the display. The windows may be formed by replacing subpixels in some of the pixels with transparent windows. When subpixels are replaced by transparent windows, adjacent subpixels may be overdriven to compensate for lost light from the replaced subpixels. Adjacent subpixels may also be enlarged to help compensate for lost light. An array of electrical components such as an array of light sensors may be aligned with the transparent windows and may be used to measure light passing through the transparent windows.