An ironworks or iron works is a building or site where iron is smelted and where heavy iron and/or steel products are made. The term is both singular and plural, i.e. the singular of ironworks is ironworks.

Ironworks succeed bloomeries when blast furnaces replaced former methods. An integrated ironworks in the 19th century usually included one or more blast furnaces and a number of puddling furnaces and/or a foundry with or without other kinds of ironworks. After the invention of the Bessemer process, converters became widespread, and the appellation steelworks replaced ironworks.