A DIN rail is a metal rail of a standard type widely used for mounting circuit breakers and industrial control equipment inside equipment racks. These products are typically made from cold rolled carbon steel sheet with a zinc-plated or chromated bright surface finish. Although metallic, they are meant only for mechanical support and are not used as a busbar to conduct electric current, though they may provide a chassis grounding connection.

The term derives from the original specifications published by Deutsches Institut für Normung (DIN) in Germany, which have since been adopted as European (EN) and international (IEC) standards. The original concept was developed and implemented in Germany in 1928, and was elaborated into the present standards in the 1950s.