The House of Saud (Arabic: آل سعود‎ Āl Suʻūd), also called the Al Saud, is the ruling royal family of Saudi Arabia. The family holds thousands of members. It is composed of the descendants of Muhammad ibn Saud and his brothers, though the ruling faction of the family is primarily led by the descendants of Abdulaziz ibn Abdul Rahman Al Saud. The family advocates Salafi Islam and unification of Arabia.

The most influential member of the family is the King of Saudi Arabia. The line of succession to the Saudi throne is not father-son but brother-brother of the children of King Abdul-Aziz. The family is estimated to be composed of 15,000 members. Most power and wealth resides amongst the 2000 or so descendants of King Abdul-Aziz.

The House of Saud has gone through three phases: the First Saudi State, the Second Saudi State, and the modern nation of Saudi Arabia. The First Saudi State marked the expansion of Salafi Islam. The Second Saudi State was marked with continuous infighting. The modern nation of Saudi Arabia wields considerable influence in the Middle East. The family has had conflicts with the Ottoman Empire, the Sharif of Mecca, and the Al Rashid family of Ha'il.

A royal family is the extended family of a king or queen regnant. The term imperial family appropriately describes the extended family of an emperor or empress, while the terms "ducal family", "grand ducal family" or "princely family" are more appropriate to describe the relatives of a reigning duke, grand duke, or prince. However, in common parlance members of any family which reigns by hereditary right are often referred to as royalty or "royals". It is also customary in some circles 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, 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 grandchildren 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 often a distinction between persons of the blood royal and those that marry into the royal family. In certain instances, such as in Canada, the royal family is defined by who holds the styles Majesty and Royal Highness. Under most systems, only persons in the first category are dynasts, that is, potential successors to the throne (unless the member of the latter category is also in line to the throne in their own right, a frequent occurrence in royal families which frequently intermarry). This is not always observed; some monarchies have operated by the principle of jure uxoris.