A steam brake is a type of brake for steam locomotives and their tenders, whereby a steam cylinder works directly on the brake linkages.
Steam brakes were primarily used on railways where vacuum brakes were used to brake the train, but where there was no vacuum brake on the steam locomotive itself, as for example in the United Kingdom, or where there was only a cable-operated brake (e.g. a Heberlein brake) running along the train, like for example in Saxony on the narrow gauge railways.
Steam brakes are usually found today on heritage steam locomotives.