| Native Name: | |
| Conventional Long Name: | Sultanate of Nejd |
| Common Name: | Nejd |
| P1: | Emirate of Nejd and Hasa |
| Flag P1: | Flag of the Emirate of Nejd and Hasa.svg |
| P2: | Emirate of Ha'il |
| Flag P2: | Flag of the Emirate of Ha'il.svg |
| P3: | Sheikdom of Upper Asir |
| Flag P3: | Flag of Upper Asir.svg |
| S1: | Kingdom of Hejaz and NejdKingdom of Hejaz and Sultanate of Nejd |
| Flag S1: | Flag of the Kingdom of Hejaz and Nejd.svg |
| Today: | Saudi Arabia |
| Flag Type: | Flag of Nejd |
| Coa Size: | 110px |
| Image Map Caption: | Sultanate of Nejd |
| Capital: | Riyadh |
| Common Languages: | Arabic |
| Religion: | Sunni Islam (Wahhabism) |
| Demonym: | Nejdi |
| Government Type: | Islamic absolute monarchy |
| Title Leader: | Sultan |
| Leader1: | Abdul Aziz ibn Saud |
| Year Leader1: | 1921–1926 |
| Title Representative: | Viceroy |
| Year Representative1: | 1921-26 |
| Year Representative2: | 1921-26 |
| Year Representative3: | 1921-26 |
| Era: | Interwar period |
| Date Start: | 2 November |
| Year Start: | 1921 |
| Event End: | Hejaz annexed |
| Date End: | 8 January |
| Year End: | 1926 |
| Legislature: | None (rule by decree) (until 1924) National Council (1924-1926) |
The Sultanate of Nejd (Arabic: سلطنة نجد, ) was the third iteration of the Third Saudi State, from 1921 to 1926. It was a monarchy led by the House of Saud, and a legal predecessor of modern-day Saudi Arabia. This version of the Third Saudi State was created when Abdul Aziz ibn Saud, Emir of Riyadh, declared himself sultan over Nejd and its dependencies.[1] On the 2 December 1922, the Nejd signed an agreement with Kuwait defining their border with each other. The border would be a straight line along the 29th parallel.[2] In December 1925, the Kingdom of Hejaz surrendered to the forces of Abdul Aziz ibn Saud, who was thereafter proclaimed king of Hejaz in January 1926 and merged his dominions into the Kingdom of Hejaz and Nejd.