The Sheffield Simplex Motor Works Ltd.. was a British automobile manufacturer that was established from 1907 to 1927 in Sheffield (Yorkshire ). Predecessor Brotherhood Crocker engine.

Sheffield - Simplex automobiles were luxury cars that were equipped with a few exceptions, with six-cylinder in-line engines. Only three slightly smaller boats have been built with four-cylinder engines.

After the First World War, the manufacturer did heavy, expensive car to sell. From 1922, only a four-cylinder model was offered, but of which emerged only a few examples. 1927 production ended for good.