Republicanism in the United Kingdom is the political movement that seeks to replace the United Kingdom's monarchy with a REPUBLIC. For those who want a non-hereditary head of state, the method by which one should be chosen is not agreed upon, with some favouring an elected president, some an appointed head of state with little power. Others support something akin to the Swiss model, with a directorate functioning as a collective head of state.

Monarchy has been the form of GOVERNMENT used in the countries that now make up the United Kingdom since the Middle Ages. However, a republican government existed in ENGLAND and Wales, later along with IRELAND and Scotland, in the mid-17th century as a result of the Parliamentarian victory in the English Civil WAR. The Commonwealth of England, as the period was called, lasted from the execution of Charles I in 1649 until the Restoration of the monarchy in 1660.

The main lobby group that campaigns for the abolition of the monarchy is Republic.