The Saudi conquest of Hejaz, also known as the Second Saudi-Hashemite War or the Hejaz-Nejd War, occurred in 1924–25. This conflict, part of the longstanding rivalry between the Hashemites of Hejaz and the Saudis of Riyadh (Nejd), led to the incorporation of Hejaz into the Saudi domain, marking the end of the Hashemite Kingdom of Hejaz.

The conflict reignited when pilgrims from Nejd were denied access to holy sites in Hejaz.^[39] Abdulaziz of Nejd initiated the campaign on 29 August 1924, capturing Taif with little resistance. Mecca fell to Saudi forces on 13 October 1924, after Sharif Hussein bin Ali's pleas for British aid were rejected. Following Mecca's fall, an Islamic Conference in Riyadh in October 1924 recognized Ibn Saud's control over the city.

As Saudi forces advanced, the Hejazi army disintegrated.^[39] Medina surrendered on 9 December 1925, followed by Yanbu. Jeddah capitulated in December 1925, with Saudi forces entering on 8 January 1926, following negotiations involving King bin Ali, Abdulaziz, and the British Consul.

Abdulaziz was proclaimed King of Hejaz following his victory, and the region was merged into the Kingdom of Nejd and Hejaz under his rule. Hussein of Hejaz, having stepped down, moved to Aqaba to support his son's military efforts but was exiled to Cyprus by the British.^[40] Ali bin Hussein assumed the Hejazi throne amidst the war, but the fall of the Kingdom led to the Hashemite dynasty's exile. Despite this, the Hashemites continued to rule in Transjordan and Iraq.