Medium-Density Fibreboard (MDF) is an engineered wood product made by breaking down hardwood or softwood residuals into wood fibres, often in a defibrator, combining it with wax and a resin binder, and forming it into panels by applying high temperature and pressure.

MDF is generally denser than plywood. It is made up of separated fibres but can be used as a building material similar in application to plywood. It is stronger and denser than particle board.