Expanded metal is a form of metal stock made by shearing a metal plate in a press, so that the metal stretches, leaving diamond-shaped voids surrounded by interlinked bars of the metal.

Expanded metal is used in outdoor furniture or fencing. Expanded metal is often used for guarding to prevent contact with hot surfaces or machinery. Expanded metal is often used for architectural details and finds use in security applications. Expanded metal is difficult to breach without heavy cutting equipment or explosives.