A royal family is the extended family of a monarch. Generally, the head of a royal family is a king or queen regnant. The term "imperial family" more appropriately describes the extended family of an emperor or empress regnant, while the terms "ducal family" or "princely family" are more appropriate in reference to the relatives of a reigning duke, grand duke, or prince. Finally, it is proper to refer to the extended relations of a deposed monarch and his or her descendants as a royal family.
A royal family typically includes the spouse of the reigning monarch, any or all surviving spouses of a deceased monarch, the children, grandchildren, brothers, sisters, and cousins of the reigning monarch, as well as their spouses. In some cases, royal family membership may extend to great granchildren and more distant descendants of a monarch. In certain monarchies where voluntary abdication is the norm, such as the Netherlands, a royal family may also include one or more former monarchs. There is a distinction between persons of the blood royal and those that marry into the royal family. Only persons in the former category are dynasts, that is, potential successors to the throne.
In general, certain relatives of the monarch (by blood or marriage) possess special privileges and are subject to certain statutes, conventions, or special common law. The precise functions of a royal family vary depending on whether the polity in question is an absolute monarchy, a constitutional monarchy, or somewhere in between. In certain absolute monarchies, such as Saudi Arabia or Kuwait, or political systems where the monarch actually exercises executive power, such as Jordan, it is not uncommon for the members of a royal family to hold important government posts or military commands. In most constitutional monarchies, however, members of a royal family perform certain public, social, or ceremonial functions, but refrain from any involvement in electoral politics or the actual governance of the country.
The specific composition of royal families varies from country to country, as do the titles and royal and noble styles held by members of the family. The composition of the royal family may be regulated by statute enacted by the legislature (e.g., Spain, the Netherlands, and Japan, since 1947), the Sovereign's prerogative and common law tradition (e.g., Great Britain), or a private house law (e.g., Litchenstein, the former royal houses of Bavaria, Prussia, Hanover, etc.). Public statutes, constitutional provisions, or conventions may also regulate the marriages, names, and personal titles of royal family members. The members of a royal family may or may not have a surname or dynastic name (see Royal House).
In a constitutional monarchy, when the monarch dies, there is always a very specific order of succession that indicates the exact order of family members in line to the throne.
In recent years, many royal families have become increasingly hounded by the media, especially tabloid newspapers.