The Kingdom of Hejaz and Nejd (Arabic: مملكة الحجاز ونجد, Mamlakat al-Ḥijāz wa-Najd), initially the Kingdom of Hejaz and Sultanate of Nejd (Arabic: مملكة الحجاز وسلطنة نجد, Mamlakat al-Ḥijāz wa-Salṭanat Najd), was a dual monarchy ruled by Abdulaziz (Ibn Saud) following the Saudi conquest of Hejaz by the Sultanate of Nejd in 1925. It was the fourth iteration of the Third Saudi State.
In 1932, the two kingdoms were unified as the Kingdom of Saudi Arabia.
Abdulaziz bin Abdul Rahman Al Saud (Arabic: عبد العزيز بن عبد الرحمن آل سعود; 15 January 1876 – 9 November 1953), known in the Western world as Ibn Saud (Arabic: ابن سعود; Ibn Suʿūd), was a Najdi statesman and tribal leader who became the founder and first king of Saudi Arabia, reigning from 23 September 1932 until his death in 1953. He had ruled parts of the kingdom since 1902, having previously been Emir, Sultan, King of Nejd, and King of Hejaz.
Ibn Saud was the son of Abdul Rahman bin Faisal, Emir of Nejd, and Sara bint Ahmed Al Sudairi. The family were exiled from their residence in the city of Riyadh in 1890. Ibn Saud reconquered Riyadh in 1902, starting three decades of conquests that made him the ruler of nearly all of central and north Arabia. He consolidated his control over Najd in 1921, then conquered the Hejaz in 1925. He extended his dominions into what later became the Kingdom of Saudi Arabia in 1932. Ibn Saud's victory and his support for Islamic revivalists would greatly bolster pan-Islamism across the Islamic world. Concording with Wahhabi beliefs, he ordered the demolition of several shrines, the Al-Baqi Cemetery and the Jannat al-Mu'alla. As King, he presided over the discovery of petroleum in Saudi Arabia in 1938 and the beginning of large-scale oil production after World War II. He fathered many children, including 45 sons, and all of the subsequent kings of Saudi Arabia as of 2025.