The HDMI splitter is a specialized accessory that is used to split an HDMI signal into many, which can then be connected to multiple display devices. An HDMI cable usually has an end that goes into the device output and another end that has two or more HDMI outputs that have been split from the single line. Alternatively, hardware splitters are connected to the output device via an HDMI cable and are used with an external power source to split the signal among multiple display devices. These cables can be configured to easily split a line among four or more displays at once.

The HDMI splitter only splits the original signal, which is shown on all of the connected devices. The image that appears on all screens will be identical and cannot be independently controlled when connected to an HDMI compatible device such as HD receivers/antennas.

The HDMI splitter is not to be confused with an HDMI routing switcher. A routing switcher places multiple HDMI compatible output sources into a signal that can be changed manually or via remote control and can dictate what output reaches the display(s).