576i is a standard-definition video mode used in (former) PAL and SECAM countries. In digital applications it is usually referred to as "576i"; in analogue contexts it is often called "625 lines", and the aspect ratio is usually 4:3 unless otherwise specified. Its NTSC counterpart is 480i; these are the two common forms of standard-definition television.

The 576 identifies a vertical resolution of 576 lines, and the i identifies it as an interlaced resolution. The field rate, which is 50 Hz, is sometimes included when identifying the video mode, i.e. 576i50; another notation, endorsed by EBU/SMPTE, includes the frame rate, as in 576i/25.

Its basic parameters common to both analogue and digital implementations are: 576 scan lines or vertical pixels of picture content, 25 frames (giving 50 fields) per second.

In analogue 49 additional lines without image content are added to the displayed frame of 576 lines to allow time for older CRT circuits to retrace for the next frame, giving 625 lines per frame. Digital information not to be displayed as part of the image can be transmitted in the non-displayed lines; teletext and other services and test signals are often implemented.