Tread plate, also known as checker plate, diamond plate and Durbar floor plate, is a type of lightweight metal stock with a regular pattern of raised diamonds or lines on one side, with the reverse side being featureless. Diamond plate is usually steel, stainless steel or aluminum. Steel types are normally made by hot rolling, although modern manufacturers also make a raised and pressed diamond design.

The added texture reduces the risk of slipping, making diamond plate a solution for stairs, catwalks, walkways, and ramps in industrial settings. Its non-skid properties mean that diamond plate is frequently used on the interior of ambulances and on the footplates of firetrucks. Additional applications include truck beds and trailer floors.

Tread plate can also be used decoratively, particularly highly polished aluminum variants. Manufactured in plastic, diamond plate is marketed as an interlocking tile system to be installed on garage floors, trailers, and exercise rooms.