The usher of the Black Rod is an official in the parliaments of several countries of the Commonwealth of Nations. The title is often shortened to Black Rod, and in some countries, formally known as Gentleman Usher of the Black Rod if male, or Lady Usher of the Black Rod if female. The position originates in the House of Lords in the Parliament of the United Kingdom. Equivalent positions also exist in Australia, Canada and New Zealand.

A serjeant-at-arms or sergeant-at-arms is an officer appointed by a deliberative body, usually a legislature, to keep order during its meetings. The word "serjeant" is derived from the Latin serviens, which means "servant". Historically, serjeants-at-arms were armed men retained by English lords and monarchs, and the ceremonial maces which they are associated with were originally a type of weapon.