The Most Honourable Order of the Bath is a British order of chivalry founded by King George I on 18 May 1725. The name derives from the elaborate medieval ceremony for appointing a knight, of which bathing (as a symbol of purification) was an element. Knights so created were known as "Knights of the Bath". George I constituted the Knights of the Bath a regular "Military Order". He did not revive the Order of the Bath, which had not previously existed as an Order, in the sense of a body of knights governed by a set of statutes and whose numbers were replenished when vacancies occurred.

The Order consists of the Sovereign (currently King Charles III), the Great Master (currently vacant) and three Classes of members:

• Knight Grand Cross (GCB) or Dame Grand Cross (GCB)
• Knight Commander (KCB) or Dame Commander (DCB)
• Companion (CB)

Members belong to either the Civil or the Military Division. Knight Companion (KB), the order's only class prior to 1815, is no longer an option. Recipients of the Order are now usually senior military officers or senior civil servants. Commonwealth citizens who are not subjects of the British monarch and foreign nationals may be made Honorary Members.

The Order of the Bath is the fourth-most senior of the British Orders of Chivalry, after The Most Noble Order of the Garter, The Most Ancient and Most Noble Order of the Thistle, and The Most Illustrious Order of St Patrick (dormant).