| Conventional Long Name: | Kingdom of Hejaz and Nejd |
| Native Name: | |
| Common Name: | Hejaz-Nejd |
| Status: | Union |
| Status Text: | Dual monarchy of the Hejaz and Nejd |
| P2: | Sultanate of Nejd |
| Flag P2: | Flag of the Sultanate of Nejd.svg |
| P1: | Kingdom of Hejaz |
| Flag P1: | Flag of Hejaz (1920).svg |
| P3: | Idrisid Emirate of Asir |
| Flag P3: | Flag of the Idrisid Emirate of Asir (1909-1927).svg |
| S1: | Kingdom of Saudi Arabia |
| Flag S1: | Saudi Arabia Flag Variant (1932).svg |
| Flag Type: | Flag of Nejd and Hejaz |
| Flag: | Flag of Saudi Arabia#History |
| Image Map Caption: | Kingdom of Hejaz and Nejd |
| Common Languages: | Arabic |
| Religion: | Islam (Wahhabism) |
| Government Type: | Islamic absolute dual monarchy |
| Title Leader: | King |
| Leader1: | Abdulaziz al Saud |
| Year Leader1: | 1926–1932 |
| Title Representative: | Viceroy |
| Year Representative1: | 1926–1932 |
| Year Representative2: | 1926–1932 |
| Year Representative3: | 1926–1932 |
| Year Representative4: | 1926–1932 |
| Legislature: | Consultative Assembly |
| Era: | Interwar period |
| Date Pre: | 19 December 1925 |
| Event Pre: | Hejaz conquered by Nejd |
| Year Start: | 1926 |
| Date Start: | 8 January |
| Event Start: | Abdulaziz crowned King of Hejaz |
| Event1: | Nejd decreed a kingdom |
| Date Event1: | 29 January 1927 |
| Year End: | 1932 |
| Date End: | 23 September |
The Kingdom of Hejaz and Nejd (Arabic: مملكة الحجاز ونجد, ), initially the Kingdom of Hejaz and Sultanate of Nejd (Arabic: Arabic: مملكة الحجاز وسلطنة نجد, ), was a dual monarchy ruled by Abdulaziz following the victory of the Saudi Sultanate of Nejd over the Hashemite Kingdom of the Hejaz in 1925. It was the fourth iteration of the Saudi State.
In 1932, the two kingdoms were unified as the Kingdom of Saudi Arabia.
On 8 January 1926, Abdulaziz, the Sultan of Nejd, was crowned King of the Hejaz in the Masjid al-Haram in Makkah, and he elevated Nejd to the status of a kingdom on 29 January 1927.[1] At the Treaty of Jeddah on 20 May 1927, Abdulaziz's realm was recognised by the United Kingdom of Great Britain and Northern Ireland, and was addressed as the Kingdom of Hejaz and Nejd.
For the next five years, Abdulaziz administered the two parts of his dual kingdom as separate units. On 23 September 1932, Abdulaziz proclaimed the union of the main Saudi dominions of al-Hasa, Qatif, Nejd and the Hejaz as the Kingdom of Saudi Arabia.
The Kingdom of Hejaz and Nejd could pursue its expansionist policy with British arms supplies because of its close relations with the United Kingdom. Under King Abdulaziz, the Hejaz withdrew from the League of Nations.
In 1926, the Kingdom of Hejaz and Nejd was recognised by the Union of Soviet Socialist Republics, followed by the United States of America in 1931. By 1932, the United Kingdom, the French Third Republic, the USSR, Turkey, the Imperial State of Iran, Kingdom of Italy and The Netherlands maintained legations in Jeddah; the Kingdom of Egypt maintained unofficial consular representatives.