The Worshipful Company of Plumbers is one of the Livery Companies of the City of London. The organisation received the right to regulate mediæval plumbers, who were, among other things, responsible for fashioning cisterns, in 1365. It was incorporated under a Royal Charter in 1611. Today, the Company is no longer a trade association, instead existing as a charitable institution. (The Company retains a link to plumbing by awarding medals and prizes in the general building industry.)

The Plumbers' Company ranks thirty-first in the order of precedence of Livery Companies. Its motto is Justicia Et Pax, Latin for Justice and Peace.